MyD88 in Mycobacterium tuberculosis infection

Identification of Differential Circular RNA Expression Profiles and Functional Networks in Human Macrophages Induced by Virulent and Avirulent Mycobacterium tuberculosis Strains

Circular RNAs (circRNAs) are noncoding RNAs with diverse functions. However, most Mycobacterium tuberculosis (M.tb)-related circRNAs remain undiscovered. In this study, we infected THP-1 cells with virulent and avirulent M.tb strains and then sequenced the cellular circRNAs. Bioinformatic analysis predicted 58,009 circRNAs in all the cells. In total, 2035 differentially expressed circRNAs were identified between the M.tb-infected and uninfected THP-1 cells and 1258 circRNAs were identified in the virulent and avirulent M.tb strains. Further, the top 10 circRNAs were confirmed by Sanger sequencing, among which four circRNAs, namely circSOD2, circCHSY1, circTNFRSF21, and circDHTKD1, which were highly differentially expressed in infected cells compared with those in uninfected cells, were further confirmed by ring formation, specific primers, and RNase R digestion. Next, circRNA-miRNA-mRNA subnetworks were constructed, such as circDHTKD1/miR-660-3p/IL-12B axis. Some of the individual downstream genes, such as miR-660-3p and IL-12B, were previously reported to be associated with cellular defense against pathological processes induced by M.tb infection. Because macrophages are important immune cells and the major host cells of M.tb, these findings provide novel ideas for exploring the M.tb pathogenesis and host defense by focusing on the regulation of circRNAs during M.tb infection.

A comprehensive approach to developing a multi-epitope vaccine against Mycobacterium tuberculosis: from in silico design to in vitro immunization evaluation

Introduction

The Bacillus Calmette-Guérin (BCG) vaccine, currently used against tuberculosis (TB), exhibits inconsistent efficacy, highlighting the need for more potent TB vaccines.

Materials and methods

In this study, we employed reverse vaccinology techniques to develop a promising multi-epitope vaccine (MEV) candidate, called PP13138R, for TB prevention. PP13138R comprises 34 epitopes, including B-cell, cytotoxic T lymphocyte, and helper T lymphocyte epitopes. Using bioinformatics and immunoinformatics tools, we assessed the physicochemical properties, structural features, and immunological characteristics of PP13138R.

Results

The vaccine candidate demonstrated excellent antigenicity, immunogenicity, and solubility without any signs of toxicity or sensitization. In silico analyses revealed that PP13138R interacts strongly with Toll-like receptor 2 and 4, stimulating innate and adaptive immune cells to produce abundant antigen-specific antibodies and cytokines. In vitro experiments further supported the efficacy of PP13138R by significantly increasing the population of IFN-γ+ T lymphocytes and the production of IFN-γ, TNF-α, IL-6, and IL-10 cytokines in active tuberculosis patients, latent tuberculosis infection individuals, and healthy controls, revealing the immunological characteristics and compare the immune responses elicited by the PP13138R vaccine across different stages of Mycobacterium tuberculosis infection.

Conclusion

These findings highlight the potential of PP13138R as a promising MEV candidate, characterized by favorable antigenicity, immunogenicity, and solubility, without any toxicity or sensitization.

Effect of kelp powder on the resistance of Aeromonas hydrophila in the gut of hybrid snakeheads (Channa maculata ♀ × Channa argus ♂)

To assess the level of oxidative stress, expression of immune-related genes, histomorphology, and changes in the intestinal tract of hybrid snakeheads(Channa maculata ♀ × Channa argus ♂) under stress from kelp powder in place of flour against Aeromonas hydrophila. We set up experimental diets: a control (C) diet of 20% flour, an experimental (MR) diet of 10% kelp powder and 10% flour, and an experimental (FR) diet of 0% starch and 15% kelp powder. The experimental fish in each group were infected with Aeromonas hydrophila after 60 days of feeding. For this experiment, some of the experimental fish in group C were injected with PBS as a negative control group (PBS). The results showed that the C group had significantly higher SOD, CAT, and T-AOC activity and expression of TAK1, IKKβ, IL-1β, and TNF-α genes in the MyD88 pathway than the PBS group. CAT activity and the expression of TAK1, IL-1β and TNF-α genes in the MyD88 pathway were significantly lower in the MR group than in the C group. Furthermore, the number of goblet cells in the MR group was significantly higher than in the C group. Furthermore, microorganisms such as Bacteroidota and Actinobacteriota were significantly lower in the C group than in the PBS and FR groups, as were beneficial bacteria such as Clostridium_sensu_stricto_1 and Sphingomonas. Replacing flour with kelp powder increases hybrid snakehead gut resistance to Aeromonas hydrophila.

An improved oral vaccine with molecular adjuvant β-defensin protects grouper against nervous necrosis virus infection

Nervous necrosis virus (NNV) is one of the most important fish viral pathogens infecting more than 120 fish species worldwide. Due to the mass mortality rates often seen among larvae and juveniles, few effective vaccines against NNV were developed up to now. Here, the protective effect of recombinant coat protein (CP) from red-spotted grouper nervous necrosis virus (RGNNV) fused with grouper β-defensin (DEFB) as an oral vaccine was evaluated using Artemia as a biocarrier delivery system in pearl gentian grouper (Epinephelus lanceolatus♂ × Epinephelus fuscoguttatus♀). Feeding with Artemia encapsulated with E. coli expressing control vector (control group), CP, or CP-DEFB showed no obvious side effects on the growth of groupers. ELISA and antibody neutralization assay showed that CP-DEFB oral vaccination group induced higher anti-RGNNV CP specific antibodies and exhibited higher neutralization potency than the CP and control group. Meanwhile, the expression levels of several immune and inflammatory factors in the spleen and kidney after feeding with CP-DEFB were also significantly increased compared with the CP group. Consistently, after challenge with RGNNV, groupers fed CP-DEFB and CP exhibited 100% and 88.23% relative percentage survival (RPS), respectively. Moreover, the lower transcription levels of viral genes and milder pathological changes in CP-DEFB group were detected compared with the CP and control group. Thus, we proposed that grouper β-defensin functioned as an efficient molecular adjuvant for an improved oral vaccine against nervous necrosis virus infection.

The role of the canonical nf-κb signaling pathway in the development of acute liver failure

As a clinical emergency with a high mortality rate, the treatment of acute liver failure has been paid attention to by society. At present, liver transplantation is the most effective treatment for acute liver failure, but there is still an insufficient supply of liver sources and a poor prognosis. In view of the current therapeutic development of this disease, more researchers have turned their attention to the research of drugs related to the NF-κB pathway. The NF-κB canonical pathway has been proven to play a role in a variety of diseases, regulating inflammation, apoptosis, and other physiological processes. More and more evidence shows that the NF-κB canonical pathway regulates the pathogenesis of acute liver failure. In this review, we will summarize the regulation process of the NF-κB canonical pathway on acute liver failure, and develop a new way to treat acute liver failure by targeting the components of the pathway.

miR-124-Antagonist-Loaded Liposomal Nanoparticles Negatively Regulate the Toll-Like Receptor (TLR)-Signaling Pathway in Alveolar Epithelial Cells in Pulmonary Tuberculosis

miR-124 is intensively expressed in the alveolar epithelial cells of pulmonary tuberculosis. This study focused on exploring the negative regulation of miR-124-antagonist-loaded liposomal nanoparticles on the Toll-like receptor (TLR)-signal transduction pathway in the alveolar epithelial cells from pulmonary tuberculosis, aiming to provide theoretical evidence for the treatment of pulmonary tuberculosis. The purchased alveolar epithelial cells were grouped into Blank group, Empty-vector group, Bacillus Calmette-Guerin (BCG) group, Nanoparticle+MiR-124 Antagonist group, MiR-124 Antagonist group, and MiR-124 Agonist group. The liposomal nanoparticles were identified. The following aspects were investigated: mRNA level of miR-124, mRNA and protein levels of Myeloid differentiation factor 88 (MyD 88), Toll-like receptor the 6 (TLR 6) and their downstream molecules Nuclear Factor-κB (NF-κB) and Tumor necrosis factor TNF receptor-associated factor 6 (TRAF 6) secretion level of cytokines (NF-κB, IL-8, IL-1α, TNF-α and IL-6), as well as the regulatory link between miR-124-antagonists with TLR6 and MyD88. The liposomal nanoparticles were uniform in size, with an average particle size of (35.25±10.58) nm and an average Zeta potential of (−48.55±10.27) mV. The miR-124 level was the strongest in the MiR-124 Agonist group, while being the lowest in the Blank group. The miR-124 level was relatively higher in the BCG group and Empty-vector group, while being significantly reduced in the Nanoparticle+MiR-124 Antagonist group, which was higher than the Blank group. The miR-124 level in the MiR-124 Antagonist group was higher than that in the Nanoparticle+MiR-124 Antagonist group (P <0.05). The mRNA and protein levels of MyD88, TLR6, NF-κB and TRAF6 were the highest in the MiR-124 Agonist group, while being the lowest in the Blank group. The transcription and translation levels of TRAF6, TLR6, NF-κB and MyD88 were relatively higher in the BCG group and Empty-vector group, while being significantly reduced in the Nanoparticle+ MiR-124 Antagonist group, which were higher than in the Blank group. The transcription and translation levels of TRAF6, TLR6, NF-κB and MyD88 were in the MiR-124 Antagonist group were higher than that in the Nanoparticle+MiR-124 Antagonist group (P <0.05). The secretion levels of inflammatory factors (NF-κB, IL-8, IL-1α, TNF-α and IL-6) were the highest in the MiR-124 Agonist group, while being the lowest in the Blank group. The levels of these inflammatory factors were relatively higher in the BCG group and Empty-vector group, while being significantly reduced in the Nanoparticle+MiR-124 Antagonist group, which were elevated compared to that in the Blank group. The secretion quantities of these inflammatory factors in the MiR-124 Antagonist group were higher than that in the Nanoparticle+MiR-124 Antagonist group (P <0.05).Dual luciferase experiments indicated that miR-124-antagonists may retard TLR6 and MyD88 to affect the immune response of pulmonary alveolar epithelial cells in pulmonary tuberculosis. The fluorescence intensity of mutant plasmid was significantly stronger than that of wild-type plasmid (P < 0.05). In the alveolar epithelial cells from pulmonary tuberculosis, the miR-124-antagonistloaded liposomal nanoparticles can significantly reduce the expression of TLR6 and MyD88, and their downstream molecules (NF-κB and TRAF6), leading to the reduced secretion of the inflammatory factors. As a result, the inflammatory response of lung tissue was alleviated, while the immune function was restored. This regulation was achieved by the miR-124-antagonist-loaded liposomal nanoparticles via negatively regulating the TLR6/MyD88 pathways.

microRNAs associated with the pathogenesis and their role in regulating various signaling pathways during Mycobacterium tuberculosis infection

Despite more than a decade of active study, tuberculosis (TB) remains a serious health concern across the world, and it is still the biggest cause of mortality in the human population. Pathogenic bacteria recognize host-induced responses and adapt to those hostile circumstances. This high level of adaptability necessitates a strong regulation of bacterial metabolic characteristics. Furthermore, the immune reponse of the host virulence factors such as host invasion, colonization, and survival must be properly coordinated by the pathogen. This can only be accomplished by close synchronization of gene expression. Understanding the molecular characteristics of mycobacterial pathogenesis in order to discover therapies that prevent or resolve illness relies on the bacterial capacity to adjust its metabolism and replication in response to various environmental cues as necessary. An extensive literature details the transcriptional alterations of host in response to in vitro environmental stressors, macrophage infection, and human illness. Various studies have recently revealed the finding of several microRNAs (miRNAs) that are believed to play an important role in the regulatory networks responsible for adaptability and virulence in Mycobacterium tuberculosis. We highlighted the growing data on the existence and quantity of several forms of miRNAs in the pathogenesis of M. tuberculosis, considered their possible relevance to disease etiology, and discussed how the miRNA-based signaling pathways regulate bacterial virulence factors.

Systemic prime exacerbates the ocular immune response to heat-killed Mycobacterium tuberculosis

Post-infectious uveitis describes the condition of chronic immune mediated ocular inflammation associated with pathogens such as Mycobacterium tuberculosis (Mtb). Mtb associated post-infectious uveitis can be modeled in mice by intravitreal injection of heat-killed Mtb (HKMtb). To better understand how prior systemic exposure to the pathogen alters the local immune response to Mtb, we used flow cytometry and multiplex ELISAs to compare ocular responses to intravitreal HKMtb in the presence or absence of a systemic "prime" of HKMtb. Priming resulted in exacerbation of local inflammation with significantly increased clinical and histologic inflammation scores and increased vitreous cytokines concentrations one day after intravitreal injection of HKMtb. Seven days after injection, uveitis in unprimed animals had largely resolved. In contrast in primed animals, clinical signs of chronic inflammation were associated with a significant increase in the number of ocular T cells, NK cells, and Ly6Chi macrophages and increasing vitreous concentrations of IL-17, VEGF, MIG(CXCL9), IP-10(CXCL10), IL-12p40 and MIP-1α(CCL3). In mice lacking mature T and B cells (RAG2 deficient), the impact of priming on the ocular immune response was ameliorated with significantly lower vitreous cytokine concentrations and spontaneous resolution of uveitis. Altogether these results suggest that the ocular response to Mtb is exacerbated by prior systemic Mtb infection and chronic post-infectious uveitis is mediated by local production of cytokines and chemokines that amplify Th17 and Th1 responses. This mouse model of chronic Mtb associated uveitis will help elucidate mechanisms of disease in patients with post-infectious uveitis.

Whole transcriptome sequencing reveals neutrophils’ transcriptional landscape associated with active tuberculosis

Neutrophils have been recognized to play an important role in the pathogenesis of tuberculosis in recent years. Interferon-induced blood transcriptional signatures in ATB are predominantly driven by neutrophils. In this study, we performed global RNA-seq on peripheral blood neutrophils from active tuberculosis patients (ATB, n=15); latent tuberculosis infections (LTBI, n=22); and healthy controls (HC, n=21). The results showed that greater perturbations of gene expression patterns happened in neutrophils from ATB individuals than HC or those with LTBI, and a total of 344 differentially expressed genes (DEGs) were observed. Functional enrichment analysis showed that besides the interferon signaling pathway, multiple pattern recognition receptor pathways were significantly activated in ATB, such as NOD-like receptors and Toll-like receptors. Meanwhile, we also observed that the expression of genes related to endocytosis, secretory granules, and neutrophils degranulation were downregulated. Our data also showed that the NF-κB signaling pathway might be inhibited in patients with ATB, which could increase Mycobacterium tuberculosis survival and lead to active tuberculosis status. Furthermore, we validated the accuracy of some differentially expressed genes in an independent cohort using quantitative PCR, and obtained three novel genes (RBM3, CSRNP1, SRSF5) with the ability to discriminate active tuberculosis from LTBI and HC.

Neuroinflammation in neurodegeneration via microbial infections

Recent epidemiological studies show a noticeable correlation between chronic microbial infections and neurological disorders. However, the underlying mechanisms are still not clear due to the biological complexity of multicellular and multiorgan interactions upon microbial infections. In this review, we show the infection leading to neurodegeneration mediated by multiorgan interconnections and neuroinflammation. Firstly, we highlight three inter-organ communications as possible routes from infection sites to the brain: nose-brain axis, lung-brain axis, and gut-brain axis. Next, we described the biological crosstalk between microglia and astrocytes upon pathogenic infection. Finally, our study indicates how neuroinflammation is a critical player in pathogen-mediated neurodegeneration. Taken together, we envision that antibiotics targeting neuro-pathogens could be a potential therapeutic strategy for neurodegeneration.

Emerging advances in identifying signal transmission molecules involved in the interaction between Mycobacterium tuberculosis and the host

Tuberculosis caused by Mycobacterium tuberculosis (MTB) is an ancient chronic infectious disease and is still the leading cause of death worldwide due to a single infectious disease. MTB can achieve immune escape by interacting with host cells through its special cell structure and secreting a variety of effector proteins. Innate immunity-related pattern recognition receptors (PPR receptors) play a key role in the regulation of signaling pathways.

In this review, we focus on the latest research progress on related signal transduction molecules in the interaction between MTB and the host. In addition, we provide new research ideas for the development of new anti-tuberculosis drug targets and lead compounds and provide an overview of information useful for approaching future tuberculosis host-oriented treatment research approaches and strategies, which has crucial scientific guiding significance and research value.

MicroRNAs: Important Regulatory Molecules in Acute Lung Injury/Acute Respiratory Distress Syndrome

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is an overactivated inflammatory response caused by direct or indirect injuries that destroy lung parenchymal cells and dramatically reduce lung function. Although some research progress has been made in recent years, the pathogenesis of ALI/ARDS remains unclear due to its heterogeneity and etiology. MicroRNAs (miRNAs), a type of small noncoding RNA, play a vital role in various diseases. In ALI/ARDS, miRNAs can regulate inflammatory and immune responses by targeting specific molecules. Regulation of miRNA expression can reduce damage and promote the recovery of ALI/ARDS. Consequently, miRNAs are considered as potential diagnostic indicators and therapeutic targets of ALI/ARDS. Given that inflammation plays an important role in the pathogenesis of ALI/ARDS, we review the miRNAs involved in the inflammatory process of ALI/ARDS to provide new ideas for the pathogenesis, clinical diagnosis, and treatment of ALI/ARDS.

Precision Vaccine Development: Cues From Natural Immunity

Traditional vaccine development against infectious diseases has been guided by the overarching aim to generate efficacious vaccines normally indicated by an antibody and/or cellular response that correlates with protection. However, this approach has been shown to be only a partially effective measure, since vaccine- and pathogen-specific immunity may not perfectly overlap. Thus, some vaccine development strategies, normally focused on targeted generation of both antigen specific antibody and T cell responses, resulting in a long-lived heterogenous and stable pool of memory lymphocytes, may benefit from better mimicking the immune response of a natural infection. However, challenges to achieving this goal remain unattended, due to gaps in our understanding of human immunity and full elucidation of infectious pathogenesis. In this review, we describe recent advances in the development of effective vaccines, focusing on how understanding the differences in the immunizing and non-immunizing immune responses to natural infections and corresponding shifts in immune ontogeny are crucial to inform the next generation of infectious disease vaccines.

Mycobacterial PPE36 Modulates Host Inflammation by Promoting E3 Ligase Smurf1-Mediated MyD88 Degradation

Mycobacterium tuberculosis (Mtb) PPE36, a cell-wall-associated protein, is highly specific and conserved for the Mtb complex group. Although PPE36 has been proven essential for iron utilization, little is known about it in regulating host immune responses. Here we exhibited that PPE36 was preferentially enriched in Mtb virulent strains and could efficiently inhibit host inflammatory responses and increase bacterial loads in infected macrophages and mice. In exploring the underlying mechanisms, we found that PPE36 could robustly inhibit the activation of inflammatory NF-κB and MAPK (Erk, p38, and Jnk) pathways by promoting E3 ligase Smurf1-mediated ubiquitination and proteasomal degradation of MyD88 protein. Our research revealed a previously unknown function of PPE36 on modulating host immune responses and provided some clues to the development of novel tuberculosis treatment strategies based on immune regulation.

Rapidly Growing Mycobacterium Species: The Long and Winding Road from Tuberculosis Vaccines to Potent Stress-Resilience Agents

Inflammatory diseases and stressor-related psychiatric disorders, for which inflammation is a risk factor, are increasing in modern Western societies. Recent studies suggest that immunoregulatory approaches are a promising tool in reducing the risk of suffering from such disorders. Specifically, the environmental saprophyte Mycobacterium vaccae National Collection of Type Cultures (NCTC) 11659 has recently gained attention for the prevention and treatment of stress-related psychiatric disorders. However, effective use requires a sophisticated understanding of the effects of M. vaccae NCTC 11659 and related rapidly growing mycobacteria (RGMs) on microbiome–gut–immune–brain interactions. This historical narrative review is intended as a first step in exploring these mechanisms and provides an overview of preclinical and clinical studies on M. vaccae NCTC 11659 and related RGMs. The overall objective of this review article is to increase the comprehension of, and interest in, the mechanisms through which M. vaccae NCTC 11659 and related RGMs promote stress resilience, with the intention of fostering novel clinical strategies for the prevention and treatment of stressor-related disorders.

Blocking of Birc3/TLR4/Myd88 signaling protects carbapenem-resistant klebsiella pneumoniae in a mouse model of infection

BACKGROUND

Klebsiella pneumonia (KP) and carbapenem-resistant Klebsiella pneumonia (CRKP) lung infections significantly increase the morbidity and mortality of pneumonia. Recent studies have shown that baculoviral IAP repeat-containing 3 (Birc3) plays an important role in the prevention and treatment of pneumonia. However, the role of Birc3 in CRKP-induced pneumonia has not been widely reported.

METHODS

In vivo, we successfully established a mouse model of pneumonia induced by KP and CRKP. In vitro, we established a macrophage model treated with KP and CRKP. The phagocytosis of macrophages treated with CRKP was measured by Flow cytometry and coated plate counting. STRING and Co-IP assays were used to predict and verify the relationship between Birc3 and toll-like receptor 4 (TLR4) or myeloid differentiation factor 88 (Myd88). HE staining was used to detect the lung pathological changes of anti-Birc3 IgG inhibited CRKP-induced inflammatory cells. The levels of inflammatory factors and proteins were detected by ELISA and Western blot, respectively.

RESULTS

The phagocytic ability of macrophages was reduced, and the cytokine storm was enhanced in CRKP treated Raw264.7 cells. Macrophages treated with CRKP impaired phagocytosis. Birc3 could interact with TLR4 and MyD88. Anti-Birc3 IgG inhibited CRKP-induced inflammatory cell lung infiltration. In addition, mice treated with anti-Birc3 IgG improved the CRKP-induced inflammatory cell lung infiltration, bacterial spread, and cytokine storm by inhibiting the Birc3/TLR4/Myd88 signaling pathway.

CONCLUSION

The results suggest that Birc3 may serve as a target for the treatment of bacterial infection and lung inflammation in CRKP-induced pneumonia.

Early pregnancy affects expression of Toll-like receptor signaling members in ovine spleen

Toll-like receptors (TLRs) are involved to the maternal immune tolerance. The spleen is essential for adaptive immune reactions. However, it is unclear that early pregnancy regulates TLR-mediated signalings in the maternal spleen. The purpose of this study was to investigate the effects of early pregnancy on expression of TLR signaling members in the ovine spleen. Ovine spleens were collected at day 16 of the estrous cycle, and at days 13, 16 and 25 of pregnancy (n = 6 for each group). Real-time quantitative PCR, western blot and immunohistochemistry analysis were used to detect TLR signaling members, including TLR2, TLR3, TLR4, TLR5, TLR7, TLR9, myeloid differentiation primary-response protein 88 (MyD88), tumor necrosis factor receptor associated factor 6 (TRAF6) and interleukin-1-receptor-associated kinase 1 (IRAK1). The results showed that expression levels of TLR2, TLR4 and IRAK1 were downregulated, but expression levels of TLR3, TLR5, TLR7, TLR9, TRAF6 and MyD88 were increased during early pregnancy. In addition, MyD88 protein was located in the capsule, trabeculae and splenic cords of the maternal spleen. This paper reports for the first time that early pregnancy has effects on TLR signaling pathways in the ovine spleen, which is beneficial for understanding the maternal immune tolerance during early pregnancy.

Sus Scrofa immune tissues as a new source of bioactive substances for skin wound healing

Influence of a new protein-peptide complex on promoting skin wound healing in male BALB/c mice was studied. Protein-peptide complex, extracted from Sus scrofa immune organs, was percutaneously administered using two methods: by lecithin gel-like liquid crystals and by liquid microemulsion. On the fifth day, wound closure in mice with a linear wound model become faster in group (less 2 days comparison to other ones), which was treated with lecithin liquid crystals carrying the protein-peptide complex. This promoting healing can be caused by resorption of bioactive high-molecular compounds the animal skin. In mice with the linear wound model, the tensile strength of the scars were respectively higher both in mice, treated using lecithin liquid crystals with protein-peptide complex, and in mice, treated using microemulsion containing protein-peptide complex, by 215.4% and 161.5% relative to the animals, which did not receive bioactive substances for wound treatment. It was associated with the regeneratory effects of tissue- and species-specific protein-peptide complexes, including α-thymosin Sus scrofa (C3VVV8_PIG, m/z 3802.8) and other factors, which were described as parts of the new extracted complex. This reveals that percutaneous administration of the complex reliably activates local regenerative processes in animals.

The role of non-coding RNA on macrophage modification in tuberculosis infection

Tuberculosis (TB), a serious disease caused by Mycobacterium tuberculosis (Mtb), remains the world's top infectious killer. It is well-established that TB can circumvent the host's immune response for long-term survival. Macrophages serve as the major host cells for TB growth and persistence and their altered functions are critical for the response of the host defense against TB exposure (elimination, latency, reactivation, and bacillary dissemination). Noncoding RNAs are crucial posttranscriptional regulators of macrophage discrimination. Therefore, this review highlights the regulatory mechanism underlying the relationship between noncoding RNAs and macrophages in TB infection, which may facilitate the identification of potential therapeutic targets and effective diagnosis biomarkers for TB disease.

Polymorphisms in TLR4 and TNFA and Risk of Mycobacterium tuberculosis Infection and Development of Active Disease in Contacts of Tuberculosis Cases in Brazil: A Prospective Cohort Study

BACKGROUND

The role of genetic polymorphisms in latent tuberculosis (TB) infection and progression to active TB is not fully understood.

METHODS

We tested the single-nucleotide polymorphisms (SNPs) rs5743708 (TLR2), rs4986791 (TLR4), rs361525 (TNFA), rs2430561 (IFNG) rs1143627 (IL1B) as risk factors for tuberculin skin test (TST) conversion or development of active TB in contacts of active TB cases. Contacts of microbiologically confirmed pulmonary TB cases were initially screened for longitudinal evaluation up to 24 months, with clinical examination and serial TST, between 1998 and 2004 at a referral center in Brazil. Data and biospecimens were collected from 526 individuals who were contacts of 177 active TB index cases. TST conversion was defined as induration ≥5 mm after a negative TST result (0 mm) at baseline or month 4 visit. Independent associations were tested using logistic regression models.

RESULTS

Among the 526 contacts, 60 had TST conversion and 44 developed active TB during follow-up. Multivariable regression analysis demonstrated that male sex (odds ratio [OR]: 2.3, 95% confidence interval [CI]: 1.1-4.6), as well as SNPs in TLR4 genes (OR: 62.8, 95% CI: 7.5-525.3) and TNFA (OR: 4.2, 95% CI: 1.9-9.5) were independently associated with TST conversion. Moreover, a positive TST at baseline (OR: 4.7, 95% CI: 2.3-9.7) and SNPs in TLR4 (OR: 6.5, 95% CI: 1.1-36.7) and TNFA (OR: 12.4, 95% CI:5.1-30.1) were independently associated with incident TB.

CONCLUSIONS

SNPs in TLR4 and TNFA predicted both TST conversion and active TB among contacts of TB cases in Brazil.

Conformational Changes Induced by S34Y and R98C Variants in the Death Domain of Myd88

Myeloid differentiating factor 88 (Myd88) is a universal adaptor protein that plays a critical role in innate immunity by mediating TLR downstream signaling. Myd88 death domain (DD) forms an oligomeric complex by association with other DD-containing proteins such as IRAK4. Despite its universal role, polymorphisms in Myd88 can result in several diseases. Previous studies have suggested that, out of several non-synonymous single-nucleotide polymorphisms (nsSNPs), the variants S34Y and R98C in the DD of Myd88 disrupt the formation of the Myddosome complex. Therefore, we performed molecular dynamics (MD) simulations on wild-type (Myd88^WT) and mutant (Myd88^S34Y, Myd88^R98C) DDs to evaluate the subtle conformational changes induced by these mutations. Our results suggest that the S34Y variant induces large structural transitions compared to the R98C variant as evidenced by residual flexibility at the variable loop regions, particularly in the H1-H2 loop, and variations in the collective modes of motion observed for wild-type and mutant Myd88 DDs. The residue interaction network strongly suggests a distortion in the interaction pattern at the location of the mutated residue between the wild type and mutants. Moreover, betweenness centrality values indicate that variations in the distribution of functionally important residues may be reflected by distinct residue signal transductions in both wild-type and mutant Myd88 DDs, which may influence the interaction with other DDs in TLR downstream signaling.

An effective live attenuated vaccine against Streptococcus agalactiae infection in farmed Nile tilapia (Oreochromis niloticus)

Streptococcus agalactiae is an important pathogen associated with various aquatic animals, especially tilapia. Streptococcosis has greatly limited the healthy development of tilapia aquaculture in recent times. The development of novel effective vaccines is important for the prevention and control of streptococcosis in fish. We previously constructed a non-encapsulated S. agalactiae strain △cps by the in-frame deletion method. Here, we evaluated whether this mutant △cps is safe for tilapia and suitable for protection against streptococcosis. We observed that the △cps strain was non-pathogenic to tilapia, and there was no reversion of virulence when it was passaged in tilapia. Moreover, the △cps strain survived for at least 11 d in the main immune organs of tilapia. The tilapia vaccinated via intraperitoneal (IP) injection with △cps strain induced a high antibody titer, and the IgM antibody levels were significantly higher in the vaccinated group than in the control group. The vaccination protected tilapia against the S. agalactiae challenge with a relative percent survival of 90.47%. In addition, tilapia immunized with the △cps strain showed significantly higher expression level of IFN-γ, IL-1β, MyD88, IgM, and MHC-Iα in the head kidney than those in the control during the entire observation period. The expression of MHC-IIβ was inhibited during 1-7 d of immunization. These results revealed that the △cps strain is able to induce humoral and cell-mediated immune response in tilapia. Therefore, the strain △cps has a broad application prospect as a target for attenuation in vaccine development.

[Mechanism of ulinastatin in reducing lung inflammatory injury in rats with hemorrhagic shock]

OBJECTIVE

To investigate the effect of ulinastatin on the inflammatory mediators and their signaling pathways miR-146a/TLR4/NF-κB in rats with hemorrhagic shock.

METHODS

Seventy-two SD rats were randomly assigned into shock without resuscitation group (SR group, n=24), acetated Ringer's solution resuscitation group (AR group, n=24) and ulinastatin treatment group (n=24). In all the 3 groups hemorrhagic shock models were established by femoral artery bleeding (with the mean arterial pressure maintained at 30-40 mmHg) without resuscitation (in SR group) or with resuscitation (in AR and ulinastatin groups) using acetated Ringer's solution for 30 min at 60 min after the onset of shock. At 1, 4, and 6 h after the shock onset or immediately after shock if the rats died, the lung tissues were taken for measurement of mRNA expressions of miR-146a, tumor necrosis factor-α (TNF-α), interleukin-1 (IL-1), IL-4, IL-6 and IL-10 using real-time quantitative PCR and the protein expressions of TLR4, MyD88, IκB-α, p-IκB-α, NF-κB p65, IRAK4, p-IRAK4 (Thr345, Ser346), p-IRAK4 (Thr342) and TRAF6 using Western blotting. The lung histopathology of the rats was examined under optical microscope with HE staining.

RESULTS

Compared with the SR group, the rats in the AR group showed slightly alleviated inflammatory infiltration in the lung tissues with significantly increased mRNA levels of miR-146a, IL-4 and IL-10 (P < 0.05) and protein expressions of IκB-α, p-IRAK4 (Thr342) and p-IRAK4 (Thr345, ser346) (P < 0.05), and decreased mRNA levels of TNF-α, IL-1 and IL-6 (P < 0.05) and protein expressions of TLR4, MyD88, NF-κB p65, p-IκB-α, IRAK-4 and TRAF6 (P < 0.05). Compared with those in AR group, the rats in ulinastatin group showed further alleviation of inflammatory lung tissue injury, with increased mRNA levels of miR-146a, IL-4 and IL-10 (P < 0.01) and protein expressions of IκB-α, p-IRAK4 and p-IRAK4 (P < 0.01) and decreased mRNA levels of TNF-α, IL-1 and IL-6 (P < 0.01) and protein expressions of TLR4, MyD88, NF-κB p65, p-IκB-α, IRAK-4 and TRAF6 (P < 0.01).

CONCLUSIONS

Ulinastatin combined with acetated Ringer's solution resuscitation alleviates lung inflammations in rats with hemorrhagic shock possibly by enhancing miR-146a expression to regulate TLR4/NF-κB signaling pathway through a negative feedback mechanism and thus modulate the balance of pro-inflammatory and anti-inflammatory factors.

Extracellular Vesicles in Mycobacterial Infections: Their Potential as Molecule Transfer Vectors

Extracellular vesicles are membrane-bound structures released by living cells and present in body fluids. Their composition includes proteins, lipids, carbohydrates, and nucleic acids and are involved in transfers between cells. Extracellular vesicles can deliver molecules to cells and tissues even if distant. As a consequence, they have a role in information transmission and in the modulation of the biological function of recipient cells. Among other things, they are involved in antigen presentation and the induction of secretion events by immune cells. Thus, extracellular vesicles participate in the regulation of immune responses during infections. We will discuss their potential as effectors and disease biomarkers concerning only mycobacterial infections.

An analysis of the expression and function of myeloid differentiation factor 88 in human osteosarcoma

The aim of the present study was to investigate the expression and function of myeloid differentiation factor 88 (MyD88) in osteosarcoma. Immunohistochemical staining was used to detect MyD88 protein in osteosarcoma tissues and matched normal bone tissues. The association between MyD88 expression and the clinical characteristics of patients with osteosarcoma was analyzed. Furthermore, survival analysis of patients with osteosarcoma was performed to study the association between MyD88 expression and patient prognosis. Finally, the effect of the MyD88 inhibitor, ST2825, on the proliferation and apoptosis of the human osteosarcoma cell line U2OS was examined. Additionally, cell proliferation, invasion and apoptosis were examined using an MTT assay, Transwell assay and Annexin V-fluorescein isothiocyanate staining kit, respectively. The expression of proteins associated with the NF-κB signaling pathway was analyzed by western blotting. The positive expression rate of MyD88 in osteosarcoma and normal bone tissues was 71.4 and 6.1%, respectively. Statistical analysis demonstrated that MyD88 was not associated with gender, age, histological type or tumor location, but that it was associated with Enneking stage and tumor metastasis (P<0.05). According to the survival analysis, patients with osteosarcoma in the high MyD88 expression group displayed a reduced overall survival rate (P<0.05). Furthermore, inhibition of MyD88 by ST2825 in U2OS cells resulted in a marked decrease in cellular proliferation and migration, and an increase in the rate of apoptosis (P<0.05). Notably, ST2825 significantly decreased cyclin D1, matrix metallopeptidase-9 and nucleus p65 expression, but increased cleaved-caspase 3 expression in ST2825-treated U2OS cells (P<0.05). The results of the present study indicated that MyD88 expression is associated with the progression of osteosarcoma and may be a potential therapeutic target for the treatment of osteosarcoma.

Effect of dexamethasone on TLR4 and MyD88 expression in monocytes of patients with tuberculous meningitis

This study aims to analyze the clinical effect of dexamethasone in the treatment of tuberculous meningitis and its effect on MyD88 and TLR4 expression in monocytes. In total, 60 tuberculous meningitis patients were divided into two groups: observation group and control group. Of them, 36 patients were treated with conventional anti-tuberculosis treatment combined with dexamethasone in the observation group, while patients in control group were treated with anti-tuberculosis alone, and the clinical efficacy and expression of TLR4 and MyD88 in peripheral blood monocytes in both the groups were analyzed. The total effective rate in the combined treatment group was 91.67%, which was significantly better than the control group (χ2 = 5.17, P < 0.05). This revealed that dexamethasone treatment can significantly reduce the expression levels of TLR4 and MyD88. Anti-tuberculosis treatment combined with dexamethasone can significantly improve treatment efficacy. Furthermore, the TLR4-MyD88 pathway plays an important role in the dexamethasone treatment of tuberculous meningitis.

Neuroinflammation and Infection: Molecular Mechanisms Associated with Dysfunction of Neurovascular Unit

Neuroinflammation is a complex inflammatory process in the central nervous system, which is sought to play an important defensive role against various pathogens, toxins or factors that induce neurodegeneration. The onset of neurodegenerative diseases and various microbial infections are counted as stimuli that can challenge the host immune system and trigger the development of neuroinflammation. The homeostatic nature of neuroinflammation is essential to maintain the neuroplasticity. Neuroinflammation is regulated by the activity of neuronal, glial, and endothelial cells within the neurovascular unit, which serves as a “platform” for the coordinated action of pro- and anti-inflammatory mechanisms. Production of inflammatory mediators (cytokines, chemokines, reactive oxygen species) by brain resident cells or cells migrating from the peripheral blood, results in the impairment of blood-brain barrier integrity, thereby further affecting the course of local inflammation. In this review, we analyzed the most recent data on the central nervous system inflammation and focused on major mechanisms of neurovascular unit dysfunction caused by neuroinflammation and infections.