Inflammatory Role of TLR-MyD88 Signaling in Multiple Sclerosis

Participation of TLRs in cancer immunopathogenesis and drug resistance via interacting with immunological and/or non-immunological signaling pathways as well as lncRNAs

Toll-like receptors (TLRs) have a convoluted role in cancer even though they are crucial to the immune system. By bridging the innate immune system and cancer, TLRs have a very complex impact on the formation of tumors and the effectiveness of anti-cancer treatments. TLR signaling links the innate and adaptive immune systems and initiates direct pathogen eradication. In cancer immunopathogenesis and treatment resistance, long non-coding RNAs (lncRNAs) modify TLR signaling linkages with immunological and non-immunological pathways. We identified lncRNAs that positively and negatively control TLR signaling, impacting immunological response and drug sensitivity. These results highlight the complex interactions between long non-coding RNAs and TLRs that influence the start of cancer and its response to treatment. Targeting specific lncRNAs is a practical way to control TLR signaling and perhaps enhance anti-tumor immunity while overcoming medication resistance. We provide a framework for developing novel immunotherapeutic regimens and customized medicine approaches for cancer treatment. The exact mechanisms by which lncRNAs regulate TLR signaling pathways should be defined by further research, and these findings should be validated in clinical situations. This finding makes future research of lncRNA-based drugs in combination with existing cancer treatments feasible.

Neurodegeneration and demyelination in multiple sclerosis

Progressive multiple sclerosis (PMS) is an immune-initiated neurodegenerative condition that lacks effective therapies. Although peripheral immune infiltration is a hallmark of relapsing-remitting MS (RRMS), PMS is associated with chronic, tissue-restricted inflammation and disease-associated reactive glial states. The effector functions of disease-associated microglia, astrocytes, and oligodendrocyte lineage cells are beginning to be defined, and recent studies have made significant progress in uncovering their pathologic implications. In this review, we discuss the immune-glia interactions that underlie demyelination, failed remyelination, and neurodegeneration with a focus on PMS. We highlight the common and divergent immune mechanisms by which glial cells acquire disease-associated phenotypes. Finally, we discuss recent advances that have revealed promising novel therapeutic targets for the treatment of PMS and other neurodegenerative diseases.

Genetically predicted N-Acetyl-L-Alanine mediates the association between CD3 on activated and secreting Tregs and Guillain-Barre syndrome

Objective

This study sought to explore the potential causal relationships among immune cell traits, Guillain-Barre syndrome (GBS) and metabolites.

Methods

Employing a two-sample Mendelian randomization (MR) approach, the study investigated the causal associations between 731 immune cell traits, 1400 metabolite levels and GBS leveraging summary-level data from a genome-wide association study (GWAS). To ensure the reliability of our findings, we further assessed horizontal pleiotropy and heterogeneity and evaluated the stability of MR results using the Leave-one-out method.

Results

This study revealed a causal relationship between CD3 on activated & secreting Tregs and GBS. Higher CD3 on activated and secreting Regulatory Tregs increased the risk of GBS (primary MR analysis odds ratio (OR) 1.31/SD increase, 95% confidence interval (CI) 1.08-1.58, p = 0.005). There was no reverse causality for GBS on CD3 on activated & secreting Tregs (p = 0.36). Plasma metabolite N-Acetyl-L-Alanine (ALA) was significantly positively correlated with GBS by using the IVW method (OR = 2.04, 95% CI, 1.26-3.30; p = 0.00038). CD3 on activated & secreting Tregs was found to be positively associated with ALA risk (IVW method, OR, 1.04; [95% CI, 1.01-1.07], p = 0.0078). Mediation MR analysis indicated the mediated proportion of CD3 on activated & secreting Tregs mediated by ALA was 10% (95%CI 2.63%, 17.4%).

Conclusion

In conclusion, our study identified a causal relationship between the level of CD3 on activated & secreting Tregs and GBS by genetic means, with a considerable proportion of the effect mediated by ALA. In clinical practice, thus providing guidance for future clinical research.

Methylation of Interleukin-1 receptor-associated kinase-3 and the risk of multiple sclerosis relapse/activity

This study retrospectively investigated the impact of interleukin-1 receptor-associated kinase-3 (IRAK-3/IRAK-M) silencing by methylation on the likelihood of multiple sclerosis (MS) activity. This cross-sectional study included 90 patients with MS: 45 with active disease (Group 1), 45 in remission (Group 2), and 45 healthy controls. The study included quantitation of IRAK-3 methylation index (MI%), IRAK-3 mRNA, and myeloid differentiation factor88 (MyD88) and assessment of NF-κB activity. IRAK-3 MI% was significantly higher in group 1 compared to group 2, accompanied by lower IRAK-3 mRNA expression, elevated circulating MyD88, and increased NF-κB activity. IRAK-3 MI% correlated negatively with its transcript and positively with MyD88 and NF-κB activity. A logistic regression model was created to predict active demyelination. The C-index was 0.924, which indicates a very strong prediction model. Within the limitations of current work, IRAK-3 methylation level seems to be a promising candidate biomarker for identifying MS patients at risk of relapse.

IRF3 regulates neuroinflammatory responses and the expression of genes associated with Alzheimer's disease

The pathological role of interferon signaling is emerging in neuroinflammatory disorders, yet, the specific role of Interferon Regulatory Factor 3 (IRF3) in neuroinflammation remains poorly understood. Here, we show that global IRF3 deficiency delays TLR4-mediated signaling in microglia and attenuates the hallmark features of LPS-induced inflammation such as cytokine release, microglial reactivity, astrocyte activation, myeloid cell infiltration, and inflammasome activation. Moreover, expression of a constitutively active IRF3 (S388D/S390D: IRF3-2D) in microglia induces a transcriptional program reminiscent of the Activated Response Microglia and the expression of genes associated with Alzheimer's disease, notably apolipoprotein-e. Using bulk-RNAseq of IRF3-2D brain myeloid cells, we identified Z-DNA binding protein-1 (ZBP1) as a target of IRF3 that is relevant across various neuroinflammatory disorders. Lastly, we show IRF3 phosphorylation and IRF3-dependent ZBP1 induction in response to Aβ in primary microglia cultures. Together, our results identify IRF3 as an important regulator of LPS and Aβ -mediated neuroinflammatory responses and highlight IRF3 as a central regulator of disease-specific gene activation in different neuroinflammatory diseases.

Vicious cycle of oxidative stress and neuroinflammation in pathophysiology of chronic vascular encephalopathy

Chronic vascular encephalopathy (CVE) is a frequent cause of vascular mild cognitive impairment and dementia, which significantly worsens the quality of life, especially in the elderly population. CVE is a result of chronic cerebral hypoperfusion, characterized by prolonged limited blood flow to the brain. This causes insufficient oxygenation of the brain leading to hypoxia. The latter can trigger a series of events associated with the development of oxidative/reductive stresses and neuroinflammation. Addressing the gap in knowledge regarding oxidative and reductive stresses in the development of vascular disorders and neuroinflammation can give a start to new directions of research in the context of CVE. In this review, we consider the hypoxia-induced molecular challenges involved in the pathophysiology of CVE, focusing on oxidative stress and neuroinflammation, which are combined in a vicious cycle of neurodegeneration. We also briefly describe therapeutic approaches to the treatment of CVE and outline the prospects for the use of sulforaphane, an isothiocyanate common in cruciferous plants, and vitamin D to break the vicious cycle and alleviate the cognitive impairments characteristic of patients with CVE.

Maternal immune activation with toll-like receptor 7 agonist during mid-gestation alters juvenile and adult developmental milestones and behavior

Infections during pregnancy are associated with increased risk for adult neuropsychiatric disease, such as major depressive disorder, schizophrenia, and autism spectrum disorder. In mouse models of maternal immune activation (MIA), different toll-like receptors (TLRs) are stimulated to initiate inflammatory responses in mother and fetus. The goal of this study was to determine sex-dependent aspects of MIA using a TLR7/8 agonist, Resiquimod (RQ), on neurodevelopment. RQ was administered to timed-pregnant mice on embryonic day (E) 12.5. At E15, maternal/fetal plasma cytokines were measured by enzyme-linked immunosorbent assay (ELISA). Maternal cytokines interleukin (IL)-6 and IL-10 were higher while tumor necrosis factor (TNF)-α and IL-17 were lower in pregnant dams exposed to RQ. Fetal cytokines (E15) were altered at the same timepoint with fetal plasma IL-6 and IL-17 greater after RQ compared to vehicle, while IL-10 and TNF-α were higher in male fetuses but not female. Other timed-pregnant dams were allowed to give birth. MIA with RQ did not alter the female to male ratio of offspring born per litter. Body weights were reduced significantly in both sexes at birth, and over the next 5 weeks. Offspring from RQ-injected mothers opened their eyes 5 days later than controls. Similarly, female offspring from RQ-injected mothers exhibited pubertal delay based on vaginal opening 2-3 days later than control females. On the behavioral side, juvenile and adult male and female MIA offspring exhibited less social-like behavior in a social interaction test. Anhedonia-like behavior was greater in MIA adult female mice. This study provides support for sex-dependent influences of fetal antecedents for altered brain development and behavioral outputs that could be indicative of increased susceptibility for adult disorders through immune mechanisms. Future studies are needed to determine neural cellular and molecular mechanisms for such programming effects.

Altered levels of IFN-γ, IL-4, and IL-5 depend on the TLR4 rs4986790 genotype in COPD smokers but not those exposed to biomass-burning smoke

Introduction

Chronic obstructive pulmonary disease (COPD) is associated with tobacco smoking and biomass-burning smoke exposure. Toll-like receptor 4 (TLR4) single-nucleotide polymorphisms (SNPs) may contribute to its pathogenesis. The study aimed to assess the association of rs4986790 and rs4986791 in the TLR4 gene in a Mexican mestizo population with COPD secondary to tobacco smoking (COPD-TS) and biomass-burning smoke (COPD-BBS) and to evaluate whether the genotypes of risk affect cytokine serum levels.

Materials and methods

We enrolled 2,092 participants and divided them into two comparisons according to their environmental exposure. SNPs were genotyped using TaqMan probes. Serum cytokine levels (IL-4, IL-5, IL-6, IL-10, and INF-γ) were quantified by ELISA.

Results

The rs4986790 AA genotype in COPD-TS was associated with a higher COPD risk (OR = 3.53). Haplotype analysis confirmed this association, identifying a block containing the rs4986790 allele (A-C, OR = 3.11). COPD-TS exhibited elevated IL-6, IL-4, and IL-5 levels compared with smokers without COPD (SWOC), whereas COPD-BBS displayed higher IFN-γ, IL-6, and IL-10 levels. The AA carriers in the COPD-TS group had elevated IL-4, IL-5, and IFN-γ compared with carriers of AG or GG.

Conclusion

The rs4986790 common allele and the A-C haplotype (rs4986790-rs4986791) were associated with a higher COPD risk in smokers; COPD patients carrying the AA genotype showed increased pro-inflammatory cytokines.

Dietary anti-inflammatory and anti-bacterial medicinal plants and its compounds in bovine mastitis associated impact on human life

Bovine mastitis (BM) is the most common bacterial mediated inflammatory disease in the dairy cattle that causes huge economic loss to the dairy industry due to decreased milk quality and quantity. Milk is the essential food in the human diet, and rich in crucial nutrients that helps in lowering the risk of diseases like hypertension, cardiovascular diseases and type 2 diabetes. The main causative agents of the disease include various gram negative, and positive bacteria, along with other risk factors such as udder shape, age, genetic, and environmental factors also contributes much for the disease. Currently, antibiotics, immunotherapy, probiotics, dry cow, and lactation therapy are commonly recommended for BM. However, these treatments can only decrease the rise of new cases but can't eliminate the causative agents, and they also exhibit several limitations. Hence, there is an urgent need of a potential source that can generate a typical and ideal treatment to overcome the limitations and eliminate the pathogens. Among the various sources, medicinal plants and its derived products always play a significant role in drug discovery against several diseases. In addition, they are also known for its low toxicity and minimum resistance features. Therefore, plants and its compounds that possess anti-inflammatory and anti-bacterial properties can serve better in bovine mastitis. In addition, the plants that are serving as a food source and possessing pharmacological properties can act even better in bovine mastitis. Hence, in this evidence-based study, we particularly review the dietary medicinal plants and derived products that are proven for anti-inflammatory and anti-bacterial effects. Moreover, the role of each dietary plant and its compounds along with possible role in the management of bovine mastitis are delineated. In this way, this article serves as a standalone source for the researchers working in this area to help in the management of BM.

Toll-like receptor 7: A novel neuroimmune target to reduce excessive alcohol consumption

Toll-like receptors (TLRs) are a family of innate immune receptors that recognize molecular patterns in foreign pathogens and intrinsic danger/damage signals from cells. TLR7 is a nucleic acid sensing endosomal TLR that is activated by single-stranded RNAs from microbes or by small noncoding RNAs that act as endogenous ligands. TLR7 signals through the MyD88 adaptor protein and activates the transcription factor interferon regulatory factor 7 (IRF7). TLR7 is found throughout the brain and is highly expressed in microglia, the main immune cells of the brain that have also been implicated in alcohol drinking in mice. Upregulation of TLR7 mRNA and protein has been identified in postmortem hippocampus and cortex from AUD subjects that correlated positively with lifetime consumption of alcohol. Similarly, Tlr7 and downstream signaling genes were upregulated in rat hippocampal and cortical slice cultures after chronic alcohol exposure and in these regions after chronic binge-like alcohol treatment in mice. In addition, repeated administration of the synthetic TLR7 agonists imiquimod (R837) or resiquimod (R848) increased voluntary alcohol drinking in different rodent models and produced sustained upregulation of IRF7 in the brain. These findings suggest that chronic TLR7 activation may drive excessive alcohol drinking. In the brain, this could occur through increased levels of endogenous TLR7 activators, like microRNAs and Y RNAs. This review explores chronic TLR7 activation as a pathway of dysregulated neuroimmune signaling in AUD and the endogenous small RNA ligands in the brain that could perpetuate innate immune responses and escalate alcohol drinking.

Moderate Prenatal Alcohol Exposure Increases Toll-like Receptor Activity in Umbilical Cord Blood at Birth: A Pilot Study

The prevalence of prenatal alcohol exposure (PAE) is increasing, with evidence suggesting that PAE is linked to an increased risk of infections. PAE is hypothesized to affect the innate immune system, which identifies pathogens through pattern recognition receptors, of which toll-like receptors (TLRs) are key components. We hypothesized that light-to-moderate PAE would impair immune responses, as measured by a heightened response in cytokine levels following TLR stimulation. Umbilical cord samples (10 controls and 8 PAE) from a subset of the Ethanol, Neurodevelopment, Infant and Child Health Study-2 cohort were included. Peripheral blood mononuclear cells (PMBCs) were stimulated with one agonist (TLR2, TLR3, TLR4, or TLR9). TLR2 agonist stimulation significantly increased pro-inflammatory interleukin-1-beta in the PAE group after 24 h. Pro- and anti-inflammatory cytokines were increased following stimulation with the TLR2 agonists. Stimulation with TLR3 or TLR9 agonists displayed minimal impact overall, but there were significant increases in the percent change of the control compared to PAE after 24 h. The results of this pilot investigation support further work into the impact on TLR2 and TLR4 response following PAE to delineate if alterations in levels of pro- and anti-inflammatory cytokines have clinical significance that could be used in patient management and/or attention to follow-up.

Toll-like receptors and integrins crosstalk

Immune system recognizes invading microbes at both pathogen and antigen levels. Toll-like receptors (TLRs) play a key role in the first-line defense against pathogens. Major functions of TLRs include cytokine and chemokine production. TLRs share common downstream signaling pathways with other receptors. The crosstalk revolving around TLRs is rather significant and complex, underscoring the intricate nature of immune system. The profiles of produced cytokines and chemokines via TLRs can be affected by other receptors. Integrins are critical heterodimeric adhesion molecules expressed on many different cells. There are studies describing synergetic or inhibitory interplay between TLRs and integrins. Thus, we reviewed the crosstalk between TLRs and integrins. Understanding the nature of the crosstalk could allow us to modulate TLR functions via integrins.

An IL-17A-centric response to Epstein-Barr virus DNA mediated by dendritic Cell-T cell interactions

Introduction: The Epstein-Barr virus has been associated with a considerable number of autoimmune diseases. We have previously demonstrated that EBV DNA enhances the production of IL-17A, a pro-inflammatory cytokine, via endosomal Toll-like receptor signalling. Methods: We used RNA-seq to analyze the transcriptional profile of mouse immune cells treated with EBV DNA. Results: We observed that EBV DNA upregulates an IL-17A-centric network of mediators. Ensemble Gene Set Enrichment Analysis (EGSEA) showed enriched expression of sets involved in inflammatory responses including IFNγ and TNF-α-associated pathways as well as proinflammatory diseases. On the other hand, while macrophages and B cells were somewhat able to induce an IL-17A response from T cells to EBV DNA, they were less potent than dendritic cells. EBV virions were also capable of eliciting the production of inflammatory mediators from dendritic cell-T cell cultures largely mirroring responses to the viral DNA. Conclusions: Given the wide prevalence of EBV in the population, our analyses reveal a network of mediators and cell types that may serve as therapeutic targets in a large proportion of people affected by autoimmune diseases.

Relationship between inflammation and oxidative stress and its effect on multiple sclerosis

INTRODUCTION

This paper highlights the relationship of inflammation and oxidative stress as damage mechanisms of Multiple Sclerosis (MS), considered an inflammatory and autoimmune disease.

DEVELOPMENT

The oxidative stress concept has been defined by an imbalance between oxidants and antioxidants in favor of the oxidants. There is necessary to do physiological functions, like the respiration chain, but in certain conditions, the production of reactive species overpassed the antioxidant systems, which could cause tissue damage. On the other hand, it is well established that inflammation is a complex reaction in the vascularized connective tissue in response to diverse stimuli. However, an unregulated prolonged inflammatory process also can induce tissue damage.

CONCLUSION

Both inflammation and oxidative stress are interrelated since one could promote the other, leading to a toxic feedback system, which contributes to the inflammatory and demyelination process in MS.

Isolation and the pathogenicity characterization of Decapod iridescent virus 1 (DIV1) from diseased Macrobrachium nipponense and its activation on host immune response

The high morbidity and mortality of Macrobrachium nipponense occurred in several farms in China, with cardinal symptoms of slow swimming, loss of appetite, empty of intestine, reddening of the hepatopancreas and gills. The pathogen has been confirmed as Decapod Iridescent Virus 1 (DIV1), namely DIV1-mn, by molecular epidemiology, histopathological examination, TEM observation, challenge experiment, and viral load detection. Histopathological analysis showed severe damage in hepatopancreas and gills of diseased prawns, exhibited few eosinophilic inclusions and pyknosis, and TEM of diseased prawns revealed that icosahedral virus particles existed in hepatopancreas and gill, which confirmed the disease of the farmed prawns caused by the DIV1 infection. Besides, challenge tests showed LD50 of DIV1 to M. nipponense was determined to be 2.14 × 104 copies/mL, and real-time PCR revealed that M. nipponense had a very high DIV1 load in the hemocytes, gills and hepatopancreas after infection. Furthermore, qRT-PCR was undertaken to investigated the expression of six immune-related genes in DIV1-infected M. nipponense after different time points, and the results revealed UCHL3, Relish, Gly-Cru2, CTL, MyD88 and Hemocyanin were significantly up-regulated in hemocytes, gills and hepatopancreas, which revealed various expression patterns in response to DIV1 infection. This study revealed that DIV1 infection is responsible for the mass mortality of M. nipponense, one of the important crustacean species, indicating its high susceptibility to DIV1. Moreover, this study will contribute to exploring the interaction between the host and DIV1 infection, specifically in terms of understanding how M. nipponense recognizes and eliminates the invading of DIV1.

Evidence supports a causal association between allele-specific vitamin D receptor binding and multiple sclerosis among Europeans

Although evidence exists for a causal association between 25-hydroxyvitamin D (25(OH)D) serum levels, and multiple sclerosis (MS), the role of variation in vitamin D receptor (VDR) binding in MS is unknown. Here, we leveraged previously identified variants associated with allele imbalance in VDR binding (VDR-binding variant; VDR-BV) in ChIP-exo data from calcitriol-stimulated lymphoblastoid cell lines and 25(OH)D serum levels from genome-wide association studies to construct genetic instrumental variables (GIVs). GIVs are composed of one or more genetic variants that serve as proxies for exposures of interest. Here, GIVs for both VDR-BVs and 25(OH)D were used in a two-sample Mendelian Randomization study to investigate the relationship between VDR binding at a locus, 25(OH)D serum levels, and MS risk. Data for 13,598 MS cases and 38,887 controls of European ancestry from Kaiser Permanente Northern California, Swedish MS studies, and the UK Biobank were included. We estimated the association between each VDR-BV GIV and MS. Significant interaction between a VDR-BV GIV and a GIV for serum 25OH(D) was evidence for a causal association between VDR-BVs and MS unbiased by pleiotropy. We observed evidence for associations between two VDR-BVs (rs2881514, rs2531804) and MS after correction for multiple tests. There was evidence of interaction between rs2881514 and a 25(OH)D GIV, providing evidence of a causal association between rs2881514 and MS. This study is the first to demonstrate evidence that variation in VDR binding at a locus contributes to MS risk. Our results are relevant to other autoimmune diseases in which vitamin D plays a role.

Nicorandil and carvedilol mitigates motor deficits in experimental autoimmune encephalomyelitis-induced multiple sclerosis: Role of TLR4/TRAF6/MAPK/NF-κB signalling cascade

Multiple sclerosis (MS) is an inflammatory demyelinating neurodegenerative disease that negatively affects neurotransmission. It can be pathologically mimicked by experimental autoimmune encephalomyelitis (EAE) animal model. ATP-sensitive potassium channels (KATP) plays a crucial role in the control of neuronal damage, however their role in MS are still obscure. Additionally, Carvedilol showed a promising neuroprotective activity against several neurological disorders. Therefore, the present study aimed to investigate the potential neuroprotective effect of KATP channel opener (nicorandil) as well as α and β adrenoceptor antagonist (Carvedilol) against EAE induced neurodegeneration in mice. Mice was treated with nicorandil (6 mg/kg/day; p.o.) and carvedilol (10 mg/kg/day; p.o.) for 14 days. Nicorandil and carvedilol showed improvement in clinical scoring, behaviour and motor coordination as established by histopathological investigation and immunohistochemical detection of MBP. Furthermore, both treatments downregulated the protein expression of TLR4/ MYD88/TRAF6 signalling cascade with downstream inhibition of (pT183/Y185)-JNK/p38 (pT180/Y182)-MAPK axis leading to reduction of neuroinflammatory status, as witnessed by reduction of NF-κB, TNF-α, IL-1β and IL-6 contents. Moreover, nicorandil and carvedilol attenuated oxidative damage by increasing Nrf2 content and SOD activity together with reduction of MDA content. In addition, an immunomodulating effect via inhibiting the gene expression of CD4, TGF-β, and IL-17 as well as TGF-β, IL-17, and IL-23 contents along with anti-apoptotic effect by decreasing Bax protein expression and Caspase-3 content and increasing Bcl-2 protein expression was observed with nicorandil and carvedilol treatments. In conclusion, nicorandil and carvedilol exerted a neuroprotective activity against EAE induced neuronal loss via inhibition of TLR4/MYD88/TRAF6/JNK/p38-MAPK axis besides antioxidant and anti-apoptotic effects.

Ginsenoside-Re inhibits experimental autoimmune encephalomyelitis as a mouse model of multiple sclerosis by downregulating TLR4/MyD88/NF-κB signaling pathways

BACKGROUND

Ginsenosides are main active compounds of Panax ginseng with pharmacological effects on immunological/neurological diseases. Recently, ginsenoside-Re (G-Re) has been shown to exert neuroprotective effects on neurodegenerative diseases such as Alzheimer's disease. However, whether G-Re has an effect on multiple sclerosis (MS), a representative autoimmune disease of the central nervous system (CNS), has not been revealed yet.

PURPOSE AND METHODS

The purpose of this study was to investigate pharmacological effects of G-Re and related molecular mechanisms using a myelin oligodendrocyte glycoprotein peptide-immunized experimental autoimmune encephalomyelitis (EAE) animal model of MS and lipopolysaccharide (LPS)-stimulated bEND.3 cells as an in vitro model of the blood-brain barrier (BBB).

RESULTS

G-Re attenuated motor impairment of EAE, demyelination, and inflammation in spinal cords of EAE mice. G-Re reduced infiltration/activation of microglia/macrophages and decreased mRNA expression levels of pro-inflammatory cytokines (IL-1β and IL-6), chemokines (MIP-1α, MCP-1, and RANTES), and enzymes (iNOS) in spinal cords of EAE mice. G-Re inhibited alterations of BBB constituents (such as astrocytes, cell adhesion molecule (platelet endothelial cell adhesion molecule-1), and tight junctional molecules (occludin and zonula occludens-1)) and toll like receptor 4 (TLR4)/MyD88/nuclear factor kappa-B (NF-κB) signaling pathways in spinal cords of EAE mice and LPS-stimulated bEND.3 cells. Interestingly, combination treatment with G-Re and TLR4 inhibitor (TAK242) significantly inhibited the upregulation of TLR4/MyD88/NF-κB pathway in LPS-stimulated bEND.3 cells. TLR4 inhibitor- and activator-treated EAE mice showed conflicting behavior patterns.

CONCLUSION

G-Re might alleviate motor impairment of EAE and its pathological/inflammatory events in the spinal cord by preventing BBB disruption via downregulation of TLR4/MyD88/NF-κB signaling pathways. These findings for the first time suggest that G-Re might be a potential therapeutic for MS through maintenance of BBB integrity.

Revolutionizing medicine with toll-like receptors: A path to strengthening cellular immunity

Toll-like receptors play a vital role in cell-mediated immunity, which is crucial for the immune system's defense against pathogens and maintenance of homeostasis. The interaction between toll-like-receptor response and cell-mediated immunity is complex and essential for effectively eliminating pathogens and maintaining immune surveillance. In addition to pathogen recognition, toll-like receptors serve as adjuvants in vaccines, as molecular sensors, and recognize specific patterns associated with pathogens and danger signals. Incorporating toll-like receptor ligands into vaccines can enhance the immune response to antigens, making them potent adjuvants. Furthermore, they bridge the innate and adaptive immune systems and improve antigen-presenting cells' capacity to process and present antigens to T cells. The intricate signaling pathways and cross-talk between toll-like-receptor and T cell receptor (TCR) signaling emphasize their pivotal role in orchestrating effective immune responses against pathogens, thus facilitating the development of innovative vaccine strategies. This article provides an overview of the current understanding of toll-like receptor response and explores their potential clinical applications. By unraveling the complex mechanisms of toll-like-receptor signaling, we can gain novel insights into immune responses and potentially develop innovative therapeutic approaches. Ongoing investigations into the toll-like-receptor response hold promise in the future in enhancing our ability to combat infections, design effective vaccines, and improve clinical outcomes.

Avicularin alleviates acute liver failure by regulation of the TLR4/MyD88/NF-κB and Nrf2/HO-1/GPX4 pathways to reduce inflammation and ferroptosis

Acute liver failure (ALF) is an inflammation-mediated hepatocyte death process associated with ferroptosis. Avicularin (AL), a Chinese herbal medicine, exerts anti-inflammatory and antioxidative effects. However, the protective effect of AL and the mechanism on ALF have not been reported. Our in vivo results suggest that AL significantly alleviated lipopolysaccharide (LPS)/D-galactosamine (D-GalN)-induced hepatic pathological injury, liver enzymes, inflammatory cytokines, reactive oxygen species and iron levels and increased the antioxidant enzyme activities (malondialdehyde and glutathione). Our further in vitro experiments demonstrated that AL suppressed inflammatory response in LPS-stimulated RAW 264.7 cells via blocking the toll-like receptor 4 (TLR4)/myeloid differentiation protein-88 (MyD88)/nuclear factor kappa B (NF-κB) pathway. Moreover, AL attenuated ferroptosis in D-GalN-induced HepG2 cells by activating the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase 1 (HO-1)/glutathione peroxidase 4 (GPX4) pathway. Therefore, AL can alleviate inflammatory response and ferroptosis in LPS/D-GalN-induced ALF, and its protective effects are associated with blocking TLR4/MyD88/NF-κB pathway and activating Nrf2/HO-1/GPX4 pathway. Moreover, AL is a promising therapeutic option for ALF and should be clinically explored.

Material matters: exploring the interplay between natural biomaterials and host immune system

Biomaterials are widely used for various medical purposes, for instance, implants, tissue engineering, medical devices, and drug delivery systems. Natural biomaterials can be obtained from proteins, carbohydrates, and cell-specific sources. However, when these biomaterials are introduced into the body, they trigger an immune response which may lead to rejection and failure of the implanted device or tissue. The immune system recognizes natural biomaterials as foreign substances and triggers the activation of several immune cells, for instance, macrophages, dendritic cells, and T cells. These cells release pro-inflammatory cytokines and chemokines, which recruit other immune cells to the implantation site. The activation of the immune system can lead to an inflammatory response, which can be beneficial or detrimental, depending on the type of natural biomaterial and the extent of the immune response. These biomaterials can also influence the immune response by modulating the behavior of immune cells. For example, biomaterials with specific surface properties, such as charge and hydrophobicity, can affect the activation and differentiation of immune cells. Additionally, biomaterials can be engineered to release immunomodulatory factors, such as anti-inflammatory cytokines, to promote a tolerogenic immune response. In conclusion, the interaction between biomaterials and the body's immune system is an intricate procedure with potential consequences for the effectiveness of therapeutics and medical devices. A better understanding of this interplay can help to design biomaterials that promote favorable immune responses and minimize adverse reactions.

Toll-like receptor-guided therapeutic intervention of human cancers: molecular and immunological perspectives

Toll-like receptors (TLRs) serve as the body's first line of defense, recognizing both pathogen-expressed molecules and host-derived molecules released from damaged or dying cells. The wide distribution of different cell types, ranging from epithelial to immune cells, highlights the crucial roles of TLRs in linking innate and adaptive immunity. Upon stimulation, TLRs binding mediates the expression of several adapter proteins and downstream kinases, that lead to the induction of several other signaling molecules such as key pro-inflammatory mediators. Indeed, extraordinary progress in immunobiological research has suggested that TLRs could represent promising targets for the therapeutic intervention of inflammation-associated diseases, autoimmune diseases, microbial infections as well as human cancers. So far, for the prevention and possible treatment of inflammatory diseases, various TLR antagonists/inhibitors have shown to be efficacious at several stages from pre-clinical evaluation to clinical trials. Therefore, the fascinating role of TLRs in modulating the human immune responses at innate as well as adaptive levels directed the scientists to opt for these immune sensor proteins as suitable targets for developing chemotherapeutics and immunotherapeutics against cancer. Hitherto, several TLR-targeting small molecules (e.g., Pam3CSK4, Poly (I:C), Poly (A:U)), chemical compounds, phytocompounds (e.g., Curcumin), peptides, and antibodies have been found to confer protection against several types of cancers. However, administration of inappropriate doses of such TLR-modulating therapeutics or a wrong infusion administration is reported to induce detrimental outcomes. This review summarizes the current findings on the molecular and structural biology of TLRs and gives an overview of the potency and promises of TLR-directed therapeutic strategies against cancers by discussing the findings from established and pipeline discoveries.

Unleashing nature's potential and limitations: Exploring molecular targeted pathways and safe alternatives for the treatment of multiple sclerosis (Review)

Driven by the limitations and obstacles of the available approaches and medications for multiple sclerosis (MS) that still cannot treat the disease, but only aid in accelerating the recovery from its attacks, the use of naturally occurring molecules as a potentially safe and effective treatment for MS is being explored in model organisms. MS is a devastating disease involving the brain and spinal cord, and its symptoms vary widely. Multiple molecular pathways are involved in the pathogenesis of the disease. The present review showcases the recent advancements in harnessing nature's resources to combat MS. By deciphering the molecular pathways involved in the pathogenesis of the disease, a wealth of potential therapeutic agents is uncovered that may revolutionize the treatment of MS. Thus, a new hope can be envisioned in the future, aiming at paving the way toward identifying novel safe alternatives to improve the lives of patients with MS.

Immunomodulatory Gene-Splicing Dysregulation in Tumorigenesis: Unmasking the Complexity

Cancer is a global health concern with rising incidence, morbidity, and mortality. The interaction between the tumor and immune cells within the tumor microenvironment is facilitated by signaling pathways driven by immunomodulatory proteins. Alternative splicing regulates the production of multiple immunomodulatory proteins with diverse functionality from a single mRNA transcript. Splicing factors are pivotal in modulating alternative splicing processes but are also subject to regulation. The dysregulation of alternative splicing may result from splicing factor (SF) abnormal expression levels and mutations in the cis and trans-acting elements and small nuclear RNA (snRNA) molecules. Aberrant splicing may generate abnormal mRNA transcripts encoding isoforms with altered functions that contribute to tumorigenesis or cancer progression. This review uncovers the complexity of immunomodulatory genes splicing dysregulation in oncogenesis. Identifying specific immunomodulatory splicing isoforms that contribute to cancer could be utilized to improve current immunotherapeutic drugs or develop novel therapeutic interventions for cancer.

Exploring the Potential of Aptamers in Targeting Neuroinflammation and Neurodegenerative Disorders: Opportunities and Challenges

Neuroinflammation is the precursor for several neurodegenerative diseases (NDDs), such as Alzheimer's disease (AD), Parkinson's disease (PD), and multiple sclerosis (MS). Targeting neuroinflammation has emerged as a promising strategy to address a wide range of CNS pathologies. These NDDs still present significant challenges in terms of limited and ineffective diagnosis and treatment options, driving the need to explore innovative and novel therapeutic alternatives. Aptamers are single-stranded nucleic acids that offer the potential for addressing these challenges through diagnostic and therapeutic applications. In this review, we summarize diagnostic and therapeutic aptamers for inflammatory biomolecules, as well as the inflammatory cells in NDDs. We also discussed the potential of short nucleotides for Aptamer-Based Targeted Brain Delivery through their unique features and modifications, as well as their ability to penetrate the blood-brain barrier. Moreover, the unprecedented opportunities and substantial challenges of using aptamers as therapeutic agents, such as drug efficacy, safety considerations, and pharmacokinetics, are also discussed. Taken together, this review assesses the potential of aptamers as a pioneering approach for target delivery to the CNS and the treatment of neuroinflammation and NDDs.

Role of neuroinflammation in neurodegeneration development

Studies in neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease and Amyotrophic lateral sclerosis, Huntington's disease, and so on, have suggested that inflammation is not only a result of neurodegeneration but also a crucial player in this process. Protein aggregates which are very common pathological phenomenon in neurodegeneration can induce neuroinflammation which further aggravates protein aggregation and neurodegeneration. Actually, inflammation even happens earlier than protein aggregation. Neuroinflammation induced by genetic variations in CNS cells or by peripheral immune cells may induce protein deposition in some susceptible population. Numerous signaling pathways and a range of CNS cells have been suggested to be involved in the pathogenesis of neurodegeneration, although they are still far from being completely understood. Due to the limited success of traditional treatment methods, blocking or enhancing inflammatory signaling pathways involved in neurodegeneration are considered to be promising strategies for the therapy of neurodegenerative diseases, and many of them have got exciting results in animal models or clinical trials. Some of them, although very few, have been approved by FDA for clinical usage. Here we comprehensively review the factors affecting neuroinflammation and the major inflammatory signaling pathways involved in the pathogenicity of neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, and Amyotrophic lateral sclerosis. We also summarize the current strategies, both in animal models and in the clinic, for the treatment of neurodegenerative diseases.

Effects of the Co-Administration of Morphine and Lipopolysaccharide on Toll-Like Receptor-4/Nuclear Factor Kappa β Signaling Pathway of MDA-MB-231 Breast Cancer Cells

Background

The Toll-like receptor 4 (TLR4) gene promotes migration in adenocarcinoma cells. Morphine is an agonist for TLR4 that has a dual role in cancer development. The promoter or inhibitor role of morphine in cancer progression remains controversial. This study aims to evaluate the effects of morphine on the TLR4, myeloid differentiation primary response protein 88-dependent (MyD88), and nuclear factor-kappa B (NF-κB) expressions in the human MDA-MB-231 breast cancer cell line.

Materials and Methods

The cells were examined after 24 hours of incubation with morphine using the Boyden chamber system. TLR4, MyD88, and NF-κB mRNA expressions were assessed using quantitative real-time polymerase chain reaction (RT-PCR). The concentration of interleukin-2 beta was also measured using the ELISA assay.

Results

According to the findings, three doses of morphine (0.25, 1.25, and 0.025 μM) increased the expression of the TLR4 and NF-κB genes, whereas no significant change was observed in the mRNA expression of MyD88. Furthermore, treatment with morphine and lipopolysaccharide (LPS) significantly decreased the expression of TLR4, MyD88, and NF-κB. However, no significant change was observed in interleukin 2 beta concentration.

Conclusions

These findings confirmed the excitatory effects of morphine on TRL4 expression and the MYD88 signaling pathway in vitro.

Myd88 Signaling Is Involved in the Inflammatory Response in LPS-Induced Mouse Epididymitis and Bone-Marrow-Derived Dendritic Cells

Epididymitis is an epididymal inflammation that may lead to male infertility. Dendritic cells (DCs) and myeloid differentiation primary response gene 88 (Myd88) were associated with epididymitis in rodents. However, the functions of Myd88 on epididymal DCs remain unclear. This study investigated the role of Myd88 in DCs for epididymitis. The Myd88 signaling pathway, phenotypes of DC subsets, and cytokines were investigated in lipopolysaccharide (LPS)-induced epididymitis in mice. CRISPR-Cas9 was used to knockout Myd88 in bone-marrow-derived dendritic cells (BMDCs) and immortalized mouse epididymal (DC2) cell line. In the vivo experiments, levels of the proinflammatory cytokines IL-1α, IL-6, IL-17A, TNF-α, IL-1β, MCP-1, and GM-CSF, mRNA for MyD88 related genes, and the percentages of monocyte-derived DCs (Mo-DCs) were significantly elevated in mice with epididymitis. In the vitro experiments, LPS significantly promoted the apoptosis of BMDCs. In addition, the concentration of inflammatory cytokines in BMDCs and DC2s were increased in the LPS group, while decreasing after the knockout of Myd88. These findings indicate that Myd88 on DCs is involved in the inflammation of epididymitis in mice, which may be a potential target for better strategies regarding the treatment of immunological male infertility.

The multitaskers of the brain: Glial responses to viral infections and associated post-infectious neurologic sequelae

Many viral infections cause acute and chronic neurologic diseases which can lead to degeneration of cortical functions. While neurotropic viruses that gain access to the central nervous system (CNS) may induce brain injury directly via infection of neurons or their supporting cells, they also alter brain function via indirect neuroimmune mechanisms that may disrupt the blood-brain barrier (BBB), eliminate synapses, and generate neurotoxic astrocytes and microglia that prevent recovery of neuronal circuits. Non-neuroinvasive, neurovirulent viruses may also trigger aberrant responses in glial cells, including those that interfere with motor and sensory behaviors, encoding of memories and executive function. Increasing evidence from human and animal studies indicate that neuroprotective antiviral responses that amplify levels of innate immune molecules dysregulate normal neuroimmune processes, even in the absence of neuroinvasion, which may persist after virus is cleared. In this review, we discuss how select emerging and re-emerging RNA viruses induce neuroimmunologic responses that lead to dysfunction of higher order processes including visuospatial recognition, learning and memory, and motor control. Identifying therapeutic targets that return the neuroimmune system to homeostasis is critical for preventing virus-induced neurodegenerative disorders.

The role of extracellular histones in COVID-19

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) had spread from China and, within 2 months, became a global pandemic. The infection from this disease can cause a diversity of symptoms ranging from asymptomatic to severe acute respiratory distress syndrome with an increased risk of vascular hyperpermeability, pulmonary inflammation, extensive lung damage, and thrombosis. One of the host defense systems against coronavirus disease 2019 (COVID-19) is the formation of neutrophil extracellular traps (NETs). Numerous studies on this disease have revealed the presence of elevated levels of NET components, such as cell-free DNA, extracellular histones, neutrophil elastase, and myeloperoxidase, in plasma, serum, and tracheal aspirates of severe COVID-19 patients. Extracellular histones, a major component of NETs, are clinically very relevant as they represent promising biomarkers and drug targets, given that several studies have identified histones as key mediators in the onset and progression of various diseases, including COVID-19. However, the role of extracellular histones in COVID-19 per se remains relatively underexplored. Histones are nuclear proteins that can be released into the extracellular space via apoptosis, necrosis, or NET formation and are then regarded as cytotoxic damage-associated molecular patterns that have the potential to damage tissues and impair organ function. This review will highlight the mechanisms of extracellular histone-mediated cytotoxicity and focus on the role that histones play in COVID-19. Thereby, this paper facilitates a bench-to-bedside view of extracellular histone-mediated cytotoxicity, its role in COVID-19, and histones as potential drug targets and biomarkers for future theranostics in the clinical treatment of COVID-19 patients.

Activation of retinal glial cells contributes to the degeneration of ganglion cells in experimental glaucoma

Elevation of intraocular pressure (IOP) is a major risk factor for neurodegeneration in glaucoma. Glial cells, which play an important role in normal functioning of retinal neurons, are well involved into retinal ganglion cell (RGC) degeneration in experimental glaucoma animal models generated by elevated IOP. In response to elevated IOP, mGluR I is first activated and Kir4.1 channels are subsequently inhibited, which leads to the activation of Müller cells. Müller cell activation is followed by a complex process, including proliferation, release of inflammatory and growth factors (gliosis). Gliosis is further regulated by several factors. Activated Müller cells contribute to RGC degeneration through generating glutamate receptor-mediated excitotoxicity, releasing cytotoxic factors and inducing microglia activation. Elevated IOP activates microglia, and following morphological and functional changes, these cells, as resident immune cells in the retina, show adaptive immune responses, including an enhanced release of pro-inflammatory factors (tumor neurosis factor-α, interleukins, etc.). These ATP and Toll-like receptor-mediated responses are further regulated by heat shock proteins, CD200R, chemokine receptors, and metabotropic purinergic receptors, may aggravate RGC loss. In the optic nerve head, astrogliosis is initiated and regulated by a complex reaction process, including purines, transmitters, chemokines, growth factors and cytokines, which contributes to RGC axon injury through releasing pro-inflammatory factors and changing extracellular matrix in glaucoma. The effects of activated glial cells on RGCs are further modified by the interplay among different types of glial cells. This review is concluded by presenting an in-depth discussion of possible research directions in this field in the future.

Suppression of MAPK/NF-kB and activation of Nrf2 signaling by Ajugarin-I in EAE model of multiple sclerosis

Multiple sclerosis (MS) is a debilitating neurodegenerative autoimmune disease of the central nervous system (CNS). The current study aimed to investigate the neuroprotective properties of Ajugarin-I (Aju-I) against the experimental autoimmune encephalomyelitis (EAE) model of MS and explored the underlying mechanism involved. The protective potential of Aju-I was first confirmed against glutamate-induced HT22 cells and hydrogen peroxide (H₂ O₂ )-induced BV2 cells. Next, an EAE model has been established to investigate the mechanisms of MS and identify potential candidates for MS treatment. The behavioral results demonstrated that Aju-I post-immunization treatment markedly reduced the EAE-associated clinical score, motor impairment, and neuropathic pain. Evans blue and fluorescein isothiocyanate extravasation in the brain were markedly reduced by Aju-I. It effectively restored the EAE-associated histopathological changes in the brain and spinal cord. It markedly attenuated EAE-induced inflammation in the CNS by reducing the expression levels of p-38/JNK/NF-κB but increased the expression of IkB-α. It suppressed oxidative stress by increasing the expression of Nrf2 but decreasing the expression of keap-1. It suppressed EAE-induced apoptosis in the CNS by regulating Bax/Bcl-2 and Caspase-3 expression. Taken together, this study suggests that Aju-I treatment exhibits neuroprotective properties in the EAE model of MS via regulation of MAPK/NF-κB, Nrf2/Keap-1, and Bcl2/Bax signaling.

The role of S100A12 and Toll-like receptor 4 in assessment of disease activity in familial Mediterranean fever and juvenile idiopathic arthritis

OBJECTIVE

Our aim was to investigate the possible relationship between the serum S100A12 and Toll-like receptor 4 (TLR4) levels, and the activity of familial Mediterranean fever (FMF) and juvenile idiopathic arthritis (JIA) in accordance with the routine biochemical parameters. Furthermore, the effectiveness of these 2 biomarkers in distinguishing FMF from JIA has been evaluated.

METHOD

Sixty-nine children with FMF, 68 children with JIA, and 35 healthy children were included in this study. S100A12 and TLR4 levels were measured by the sandwich enzyme-linked immunosorbent assay technique.

RESULTS

In the FMF patient group, serum S100A12 level was found to be significantly higher than in both the JIA and control groups (P = .000 and P = .000, respectively). Although S100A12 levels were higher in the attack period compared to the attack-free period, this increase was not statistically significant (P > .05). TLR4 levels were statistically significantly higher in the attack period compared to the attack-free period in children with FMF (P < .05). Although there was no relationship between S100A12 levels and disease activity, there is a clear correlation between S100A12 and the Auto-Inflammatory Disease Activity Index in attack-free FMF patients (r = 0.612 P = .000).

CONCLUSION

Serum S100A12 levels were not found to be a potentially valuable biomarker for assessing disease activity in either FMF or JIA. However, TLR4 levels were found to be a valuable biomarker for assessing disease activity in children with FMF. Further research which includes serial monitoring of S100A12 and TLR4 levels in a large cohort will provide detailed information about accuracy of these 2 potential biomarkers in both patients group.

Therapeutic immunomodulation by rationally designed nucleic acids and nucleic acid nanoparticles

The immune system has evolved to defend organisms against exogenous threats such as viruses, bacteria, fungi, and parasites by distinguishing between "self" and "non-self". In addition, it guards us against other diseases, such as cancer, by detecting and responding to transformed and senescent cells. However, for survival and propagation, the altered cells and invading pathogens often employ a wide range of mechanisms to avoid, inhibit, or manipulate the immunorecognition. As such, the development of new modes of therapeutic intervention to augment protective and prevent harmful immune responses is desirable. Nucleic acids are biopolymers essential for all forms of life and, therefore, delineating the complex defensive mechanisms developed against non-self nucleic acids can offer an exciting avenue for future biomedicine. Nucleic acid technologies have already established numerous approaches in therapy and biotechnology; recently, rationally designed nucleic acids nanoparticles (NANPs) with regulated physiochemical properties and biological activities has expanded our repertoire of therapeutic options. When compared to conventional therapeutic nucleic acids (TNAs), NANP technologies can be rendered more beneficial for synchronized delivery of multiple TNAs with defined stabilities, immunological profiles, and therapeutic functions. This review highlights several recent advances and possible future directions of TNA and NANP technologies that are under development for controlled immunomodulation.

Molecular mechanism of the anti-inflammatory effects of plant essential oils: A systematic review

ETHNOPHARMACOLOGICAL RELEVANCE

Plant essential oils (PEOs) extracted from aromatic compounds of the plant contain complex mixtures of volatile and lipophilic bioactive compounds. In ancient Egypt, Arabia, Greece, and China, PEOs were traditional used in aromatherapy for various health disorders, including pain and inflammation.

AIM OF THE STUDY

In this review, we provide an overview of the anti-inflammatory effects of PEOs and the underlying mechanisms associated with anti-inflammatory effects using in vitro and in vivo models. Further, clinical trials associated with PEOs were explored.

MATERIALS AND METHODS

The literature search was performed using various web-based tools and databases like Google Scholar, Web of Science, PubMed, CNKI and SCOPUS. The keywords used for conducting the literature review were general terms like "essential oils" followed by (AND) the subject of interest like "in vitro and/or in vivo anti-inflammatory models," "inflammatory response," "inflammatory indicators," "pro-inflammatory cytokines," "signaling pathway," "anti-inflammatory mechanism," "toxicology and side effects" and "clinical trials." The articles selected were published between 2017 and 2022. The articles prior to 2017 were only considered if they were associated with molecular mechanisms or signaling pathways involved in the inflammatory responses.

RESULTS

In vitro and in vivo inflammation models have been used to study the anti-inflammatory effects of 48 PEOs. Studies have reported that PEOs targets and inhibit multiple dysregulated signaling pathways associated with inflammation, including Toll-like receptors, nuclear transcription factor-κ B, mitogen-activated protein kinases, Nod-like receptor family pyrin domain containing 3, and auxiliary pathways like the nuclear factor erythroid 2-related factor 2/antioxidant response element and Janus kinase/signal transducers and activators of transcription) signaling pathways.

CONCLUSION

PEOs extracted from different plant materials had varied qualitative and quantitative compositions of biologically active compounds. Different anti-inflammatory potentials and different molecular signal transduction have been attributed to PEOs-derived bioactive compounds with different chemical structures. The data on therapeutic efficacy and the long-term side effects of PEOs as an anti-inflammatory drug are still unknown due to the lack of clinical trials on PEOs. There is still insufficient evidence to draw conclusions on anti-inflammatory properties of PEOs without promising outcomes from clinical trials.

Role of TLRs in HIV-1 Infection and Potential of TLR Agonists in HIV-1 Vaccine Development and Treatment Strategies

Toll-like receptors (TLRs), as a family of pattern recognition receptors, play an important role in the recognition of HIV-1 molecular structures by various cells of the innate immune system, but also provide a functional association with subsequent mechanisms of adaptive immunity. TLR7 and TLR8 play a particularly important role in the innate immune response to RNA viruses due to their ability to recognise GU-rich single-stranded RNA molecules and subsequently activate intracellular signalling pathways resulting in expression of genes coding for various biological response modifiers (interferons, proinflammatory cytokines, chemokines). The aim of this review is to summarise the most recent knowledge on the role of TLRs in the innate immune response to HIV-1 and the role of TLR gene polymorphisms in the biology and in the clinical aspects of HIV infections. In addition, the role of TLR agonists as latency reversing agents in research to treat HIV infections and as immunomodulators in HIV vaccine research will be discussed.

TLR4/ MyD88/NF-κB signaling pathway involved in the protective effect of diacerein against lung fibrosis in rats

PURPOSE

Pulmonary fibrosis (PF) is an inescapable problem. Diacerein, a chondro-protective drug, has antioxidant and anti-inflammatory effects. Its effect on PF injury has not yet been fully clarified. Therefore, the current study aimed to detect its protective effect on lung tissue with the explanation of possible underlying mechanisms.

METHODS

Adult male albino rats were assigned to four groups: control group, diacerein control group, PF non-treated group, and PF diacerein pretreated group. Lung tissue oxidative stress parameters, inflammatory biomarkers mainly Toll-like receptors-4 (TLR4), and myeloid differentiation factor 88 (MyD88) levels were determined. Histopathological examination of lung tissue and immunohistochemical studies of nuclear factor-kappa B (NF-κB), and transforming growth factor- β (TGF-β) were also done.

RESULTS

Diacerein pretreatment has the ability to restore the PF damaging effect, proved by the reduction of the oxidative stress and lung tissue inflammation via downregulation of TLR4/NF-κB signaling pathway together with the restoration of TGF-β level and improvement of the histopathological and immunohistochemical study findings in the lung tissue.

CONCLUSION

These results suggested the protective effect of diacerein on PF relies on its antioxidant and anti-inflammatory effects reducing TLR4/NF-κB signaling pathway.

Synthesis of 1-(5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazol-3-yl)-2-morpholinoethane-1,2-dione analogues and their inhibitory activities with reduced cytotoxicity in lipopolysaccharide-induced BV2 cells

A series of rimonabant analogues, where the N-aminopiperidine moiety was replaced by various amines and an additional carbonyl group, were synthesized and their inhibition of nitric oxide (NO) production was evaluated in lipopolysaccharide (LPS)-induced BV2 microglial cells. Among the synthesized compounds, the morpholine analogue 7y (IC₅₀ = 4.71 ± 0.11 μM) showed significantly higher inhibitory activity than rimonabant (IC₅₀ = 16.17 ± 0.56 μM), and suppressed NO production dose-dependently without cytotoxicity. In addition, 7y inhibited the expression of iNOS, COX-2 and pro-inflammatory cytokines and attenuated LPS-induced activation of nuclear factor-kappa B (NF-κB) and ERK MAPK phosphorylation in BV2 cells. These results demonstrated that 7y exerted anti-inflammatory effects by ERK pathway in BV2 cells, which can be used for the prevention and treatment of neuroinflammatory diseases.

Discovery of grey matter lesion-related immune genes for diagnostic prediction in multiple sclerosis

Background

Multiple sclerosis (MS) is a chronic debilitating disease characterized by inflammatory demyelination of the central nervous system. Grey matter (GM) lesions have been shown to be closely related to MS motor deficits and cognitive impairment. In this study, GM lesion-related genes for diagnosis and immune status in MS were investigated.

Methods

Gene Expression Omnibus (GEO) databases were utilized to analyze RNA-seq data for GM lesions in MS. Differentially expressed genes (DEGs) were identified. Weighted gene co-expression network analysis (WGCNA), least absolute shrinkage and selection operator (LASSO) algorithm and protein-protein interaction (PPI) network were used to screen related gene modules and candidate genes. The abundance of immune cell infiltration was analyzed by the CIBERSORT algorithm. Candidate genes with strong correlation with immune cell types were determined to be hub genes. A diagnosis model of nomogram was constructed based on the hub genes. Gene set enrichment analysis (GSEA) was performed to identify the biological functions of hub genes. Finally, an MS mouse model was induced to verify the expression levels of immune hub genes.

Results

Nine genes were identified by WGCNA, LASSO regression and PPI network. The infiltration of immune cells was significantly different between the MS and control groups. Four genes were identified as GM lesion-related hub genes. A reliable prediction model was established by nomogram and verified by calibration, decision curve analysis and receiver operating characteristic curves. GSEA indicated that the hub genes were mainly enriched in cell adhesion molecules, cytokine-cytokine receptor interaction and the JAK-STAT signaling pathway, etc.

Conclusions

TLR9, CCL5, CXCL8 and PDGFRB were identified as potential biomarkers for GM injury in MS. The effectively predicted diagnosis model will provide guidance for therapeutic intervention of MS.

Rao G, Rai S. Microbiota milieu and mechanisms of intestinal Toll Like Receptors (TLRs) involved in chemotherapy induced mucositis

Gut is not only of digestive but also of immunological importance because of the residing microbiota milieu. Pathological or certain therapeutic condition may modify the normal commensal microflora. Mucositis, the most common untoward effect of chemotherapy, can also lead to this microbiotic imbalance. This shift leads to various molecular cascades which in turn trigger the action of Pattern Recognition Receptors (PRR’s). Toll like receptor (TLR) is one such pattern recognition receptor. In the human body there are about 13 types of TLRs out of which TLR-2, TLR-4, TLR-5 and TLR-9 are intestinal specific. They respond through ligands such as bacterial derivatives like flagellin, Lipoteichoic acid, Lipopolysaccharides, microbial antigen or genetic material of the viru. In turn via adaptor molecules, TLRs alter the signalling mechanisms and further induct the activation of pro or anti-inflammatory cytokines based on the immunological need. Several of the studies have described the involvement of under twined mechanisms of TLRs during chemotherapy. Therefore, agonists and/or antagonists of these strategic molecules may play a key role in pathological and therapeutic aspects. Thus, this review is an attempt to focus on the involvement of TLRs and microbiota to different chemotherapeutic agents and thereby track the available mechanisms of functionality.

β-caryophyllene and docosahexaenoic acid, isolated or associated, have potential antinociceptive and anti-inflammatory effects in vitro and in vivo

Inflammation is a complex biological response involving the immune, autonomic, vascular, and somatosensory systems that occurs through the synthesis of inflammatory mediators and pain induction by the activation of nociceptors. Staphylococcus aureus, the main cause of bacteremia, is one of the most common and potent causes of inflammation in public health, with worse clinical outcomes in hospitals. Antioxidant substances have been evaluated as alternative therapeutic analgesics, antioxidants, anti-inflammatory agents, antitumor agents, and bactericides. Among these, we highlight the essential oils of aromatic plants, such as β-caryophyllene (BCP), and polyunsaturated fatty acids, such as docosahexaenoic acid (DHA). The objective of this study was to evaluate the biological activities of BCP-DHA association in in vitro and in vivo experimental models of antinociception and inflammation. To determine the anti-inflammatory effects, monocytes isolated from the peripheral blood of adult male volunteers were infected with methicillin-resistant S. aureus and incubated with treatment for cytokine dosage and gene expression analysis. Antinociceptive effects were observed in the three models when comparing the control (saline) and the BCP-DHA treatment groups. For this purpose, the antinociceptive effects were evaluated in animal models using the following tests: acetic acid-induced abdominal writhing, paw edema induced by formalin intraplantar injection, and von Frey hypernociception. There was a significant reduction in the GM-CSF, TNFα, IL-1, IL-6, and IL-12 levels and an increase in IL-10 levels in the BCP-DHA treatment groups, in addition to negative regulation of the expression of the genes involved in the intracellular inflammatory signaling cascade (IL-2, IL-6, IRF7, NLRP3, and TYK2) in all groups receiving treatment, regardless of the presence of infection. Statistically significant results (p < 0.05) were obtained in the acetic acid-induced abdominal writhing test, evaluation of paw edema, evaluation of paw flinching and licking in the formalin intraplantar injection model, and the von Frey hypernociception test. Therefore, BCP and DHA, either administered individually or combined, demonstrate potent anti-inflammatory and antinociceptive effects.

Improvement in the Immunity- and Vitamin D3-Activity-Related Gene Expression of Coccidiosis-Challenged Ross 708 Broilers in Response to the In Ovo Injection of 25-Hydroxyvitamin D3

Effects of the in ovo administration of two vitamin D3 sources (vitamin D3 (D3) and 25-hydroxyvitamin D3 (25OHD3)) on the expression of D3 activity- and immunity-related genes in broilers subjected to a coccidiosis infection were investigated. At 18 d of incubation (doi), five in ovo injection treatments were administrated to live embryonated Ross 708 broiler hatching eggs: non-injected (1) and diluent-injected (2) controls, or diluent injection containing 2.4 μg of D3 (3) or 2.4 μg of 25OHD3 (4), or their combination (5). Birds in the in ovo-injected treatments were challenged at 14 d of age (doa) with a 20× dosage of a live coccidial vaccine. At 14 and 28 doa, the expression of eight immunity-related genes (IL-2, IL-6, IL-10, TLR-4, TLR-15, MyD88, TGF-β4, and IFN-γ) and four D3 activity-related genes (1α-hydroxylase, 25-hydroxylase, 24-hydroxylase, and VDR) in the jejunum of one bird in each treatment-replicate group were evaluated. No significant treatment effects were observed for any of the genes before challenge. However, at 2 weeks post-challenge, the expression of 1α-hydroxylase, TGF-β4, and IL-10 increased in birds that received 25OHD3 alone in comparison to all the other in ovo-injected treatment groups. Additionally, the expression of 24-hydroxylase and IL-6 decreased in birds that received 25OHD3 in comparison to those injected with diluent or D3 alone. It was concluded that the in ovo injection of 2.4 μg of 25OHD3 may improve the intestinal immunity as well as the activity of D3 in Ross 708 broilers subjected to a coccidiosis challenge.

Expression of cathelicidin, ERK, MyD88, and TLR-9 in the blood of women in the pre-pregnancy, pregnancy, and their infant cord blood

During pregnancy, the immune responses are modulated to protect mothers and infants from different pathogens. Cathelicidin as an antimicrobial peptide has a defending role against many pathogens. In this study, to better understand the role of cathelicidin peptide and three of its related proteins in immune pathways (ERK, MyD88, and TLR-9) in the immune system during pregnancy, we examined their expression in the blood of non-pregnant and pregnant mothers and their infant's cord blood. Blood samples were taken, and their peripheral blood mononuclear cells (PBMCs) were obtained. The expression level of cathelicidin was determined by quantitative PCR. Also, the expression of cathelicidin, ERK, MyD88, and TLR-9 was assessed by Western blotting. Higher level of cathelicidin mRNA was detected in the cord blood samples compared to other samples. The Western blotting results showed higher levels of cathelicidin, ERK, MyD88, and TLR-9 in the cord blood samples than in the blood of both pregnant and non-pregnant samples. Also, the level of all molecules was higher in pregnant than non-pregnant women. These high levels of the mentioned molecules are necessary to protect the mother and fetus against various pathogens, although understanding their mechanism of action needs more studies.

Toll-like receptor-mediated neuroinflammation: relevance for cognitive dysfunctions

Toll-like receptors (TLRs) are pattern recognition receptors (PRRs) with a well-documented role in the innate and adaptive immune responses. Interestingly, TLR activation has also been linked to several brain functions including neurogenesis and synaptogenesis. Increasing evidence supports TLR involvement in peripheral and central inflammation underlying normal aging and the pathogenesis of clinical conditions characterized by cognitive decline. These include not only major neurodegenerative diseases but also traumatic brain injuries, surgeries, and alcohol consumption- and chemotherapy-induced cognitive impairment. We first summarize the physiological roles of TLRs in the nervous system, and then illustrate the emerging involvement of TLRs in cognitive functions, pointing to these receptors as novel enticing pharmacological targets to develop more efficient drugs for the treatment of cognitive impairment.

Emerging role of mesenchymal stromal cells (MSCs)-derived exosome in neurodegeneration-associated conditions: a groundbreaking cell-free approach

Accumulating proofs signify that pleiotropic effects of mesenchymal stromal cells (MSCs) are not allied to their differentiation competencies but rather are mediated mainly by the releases of soluble paracrine mediators, making them a reasonable therapeutic option to enable damaged tissue repair. Due to their unique immunomodulatory and regenerative attributes, the MSC-derived exosomes hold great potential to treat neurodegeneration-associated neurological diseases. Exosome treatment circumvents drawbacks regarding the direct administration of MSCs, such as tumor formation or reduced infiltration and migration to brain tissue. Noteworthy, MSCs-derived exosomes can cross the blood-brain barrier (BBB) and then efficiently deliver their cargo (e.g., protein, miRNAs, lipid, and mRNA) to damaged brain tissue. These biomolecules influence various biological processes (e.g., survival, proliferation, migration, etc.) in neurons, oligodendrocytes, and astrocytes. Various studies have shown that the systemic or local administration of MSCs-derived exosome could lead to the favored outcome in animals with neurodegeneration-associated disease mainly by supporting BBB integrity, eliciting pro-angiogenic effects, attenuating neuroinflammation, and promoting neurogenesis in vivo. In the present review, we will deliver an overview of the therapeutic benefits of MSCs-derived exosome therapy to ameliorate the pathological symptoms of acute and chronic neurodegenerative disease. Also, the underlying mechanism behind these favored effects has been elucidated.

A microsatellite DNA-derived oligodeoxynucleotide attenuates lipopolysaccharide-induced acute lung injury in mice by inhibiting the HMGB1-TLR4-NF-κB signaling pathway

Acute lung injury (ALI) with uncontrolled inflammatory response has high morbidity and mortality rates in critically ill patients. Pathogen-associated molecular patterns (PAMPs) are involved in the development of uncontrolled inflammatory response injury and associated lethality. In this study, we investigated the inhibit effect of MS19, a microsatellite DNA-derived oligodeoxynucleotide (ODN) with AAAG repeats, on the inflammatory response induced by various PAMPs in vitro and in vivo. In parallel, a microsatellite DNA with AAAC repeats, named as MS19-C, was used as controls. We found that MS19 extensively inhibited the expression of inflammatory cytokines interleukin (IL)-6 and tumor necrosis factor (TNF)-α induced by various PAMPs stimulation, including DNA viruses, RNA viruses, bacterial components lipopolysaccharide (LPS), and curdlan, as well as the dsDNA and dsRNA mimics, in primed bone marrow-derived macrophage (BMDM). Other than various PAMPs, MS19 also demonstrated obvious effects on blocking the high mobility group box1 (HMGB1), a representative damage-associated-molecular pattern (DAMP), nuclear translocation and secretion. With the base substitution from G to C, MS19-C has been proved that it has lost the inhibitory effect. The inhibition is associated with nuclear factor kappa B (NF-κB) signaling but not the mitogen-activated protein kinase (MAPK) transduction. Moreover, MS19 capable of inhibiting the IL-6 and TNF-α production and blocking the HMGB1 nuclear translocation and secretion in LPS-stimulated cells was used to treat mice ALI induced by LPS in vivo. In the ALI mice model, MS19 significantly inhibited the weight loss and displayed the dramatic effect on lessening the ALI by reducing consolidation, hemorrhage, intra-alveolar edema in lungs of the mice. Meanwhile, MS19 could increase the survival rate of ALI by downregulating the inflammation cytokines HMGB1, TNF-a, and IL-6 production in the bronchoalveolar lavage fluid (BALF). The data suggest that MS19 might display its therapeutic role on ALI by inhibiting the HMGB1-TLR4-NF-κB signaling pathway.

Pharmacogenetic analysis of canonical versus noncanonical pathway of NF-kB in Crohn's disease patients under anti-tumor necrosis factor-α treatment

OBJECTIVES

This study explores the potential of gene polymorphisms in the canonical and noncanonical NF-kB signaling pathway as a prediction biomarker of anti-tumor necrosis factor (TNF)α response in Crohn's patients.

MATERIALS AND METHODS

A total of 109 Greek patients with Crohn's disease (CD) were recruited, and the genotype of TLR2 rs3804099, LTA rs909253, TLR4 rs5030728, and MAP3K14/NIK rs7222094 single nucleotide polymorphisms was investigated for association with response to anti-TNFα therapy. Patient's response to therapy was based on the Crohn's Disease Activity Index, depicting the maximum response within 24 months after initiation of treatment.

RESULTS

Seventy-three patients (66.7%) were classified as responders while 36 as nonresponders (33.3%). Comparing allelic frequencies between responders and nonresponders, the presence of TLR2 rs3804099 T allele was associated with nonresponse (P = 0.003), even after stratification by anti-TNFα drugs (infliximab: P = 0.032, adalimumab: P = 0.026). No other association was identified for the rest of the polymorphisms under study. Haplotype analysis further enhanced the association of rs3804099 T allele with loss of response, even though the results were NS (P = 0.073).

CONCLUSION

Our results suggest that polymorphisms in the canonical NF-kB pathway genes could potentially act as a predictive biomarker of anti-TNFα response in CD.

Acteoside promotes B cell-derived IL-10 production and ameliorates autoimmunity

IL-10-producing regulatory B (Breg) cells are well recognized for maintaining immune tolerance. The impaired Breg cell function with decreased IL-10-producing capacity has been found in autoimmune diseases, such as rheumatoid arthritis, lupus, and primary Sjogren's syndrome (pSS). However, seldom therapeutic agents targeting Breg cells are available to treat those autoimmune diseases. Here, we showed that acteoside (AC), a caffeoyl phenylethanoid glycoside from a medicinal herb Radix Rehmanniae, could promote IL-10 production from both human and murine B cells via critically regulating the TLR4/PI3K axis. Moreover, TLR4 was found increased in Breg cells from mice with experimental SS (ESS), a mouse model that recapitulates human pSS. Thus, B cells from the ESS mice were susceptible to AC treatment, showing higher IL-10-producing capacity than those from naïve controls. In addition, AC treatment also promoted the production of IL-10 from TLR4⁺ CXCR4⁺ plasma cells of ESS mice. Notably, we found that AC was able to enter lymphoid organs upon oral administration. AC treatment effectively increased IL-10⁺ B cells in ESS mice and ameliorated disease pathology accompanied by reduced T effector cells, including Th17 and T follicular helper cells in the ESS mice. In conclusion, AC could promote Breg cell function and attenuate ESS pathology in vivo, which may be a promising drug candidate for treating pSS and other autoimmune diseases.

Evidence for investigating GSK-3 inhibitors as potential therapeutics for severe COVID-19

A key component of severe COVID-19 is a "cytokine storm" i.e., the excessive expression of unneeded cytokines. Previous studies suggest that SARS-CoV-2 proteins can induce macrophages to secrete pro-inflammatory cytokines; a process that may involve Toll-like receptors (TLRs). Glycogen synthase kinase-3 (GSK-3) has been implicated in TLR signal transduction and a selective GSK-3 inhibitor, termed COB-187, dramatically attenuates cytokine expression induced by the TLR ligand lipopolysaccharide (LPS). In the present study, we provide evidence that the SARS-CoV-2 spike protein (S) and the S2 subunit (S2) induce production of CXCL10 (a chemokine elevated in severe COVID-19) by a human macrophage cell line. Further, we report that two clinically relevant GSK-3 inhibitors and COB-187 attenuate S and S2 protein-induced CXCL10 production. Combined, our observations provide impetus for investigating GSK-3 inhibitors as potential therapeutics for severe COVID-19.