TLR4 mutations are associated with endotoxin hyporesponsiveness in humans

Toll-like receptors polymorphisms and COVID-19: a systematic review

COVID-19 is a disease caused by SARS-CoV-2. It became a health problem affecting the lives of millions of people. Toll-like receptors are responsible for recognizing viral particles and activating the innate immune system. The genetic factors associated with COVID-19 remain unclear. Thus, this study aims to assess the association between the polymorphism in Toll-like receptors and susceptibility to COVID-19. We searched the electronic databases (Science Direct, PUBMED, Web of Science, and Scopus) for studies assessing the association between Toll-like receptor polymorphisms and susceptibility to COVID-19. The quality of the studies was assessed using the Q-Genie tool. Thirteen studies were included in this systematic review. The studies analyzed polymorphisms in TLR2, TLR3, TLR4, TLR7, TLR8 and TLR9. We used SNP2TFBS bioinformatic analysis to identify the variants influencing transcription factor binding sites. The Ensembl Genome Browser was used to assess the allele and genotype frequencies in different populations. The bioinformatic analysis revealed that the variant rs5743836 of TLR9 affects the transcription factor binding sites NFKB1 and RELA. The genotype frequency of the variants rs3775291, rs3853839, rs3764880 were higher in East Asian population compared to the other populations. The frequency of the rs3775290 variant was higher in East and South Asian populations. The rs179008 variant was higher in the European population, and the rs5743836 was higher in the African population. Toll-like receptors play an important role in COVID-19 susceptibility. Further studies in different populations are necessary to elucidate the role of Toll-like receptors polymorphisms in SARS-CoV-2 infection.

Features of toll-like receptor genes (TLR-2, TLR-3, TLR-4 and TLR-6) polymorphism in open-angle glaucoma patients

Modern research shows that innate immunity plays an important role in the pathogenesis of primary open-angle glaucoma (POAG). An increase in the content of toll-like receptors (TLR) in the glaucomatous retina of the human eye was revealed. TLRs can modulate the immune response in glaucoma; provide early recognition of damaging agents, activation of signaling pathways and effector mechanisms of the nonspecific immune defense system aimed at restoring homeostasis. The TLR-encoding genes' polymorphism alters the amino acid structure of the receptors, which leads to changes in their immune functions: expression level, ligand-binding and coreceptor functions, transport and signal transmission. The aim was to analyze the association of the TLR2 (rs5743708), TLR3 (rs3775291), TLR4 (rs4986790, rs4986791) and TLR6 (rs5743810) polymorphisms with primary open-angle glaucoma in patients of Western Siberia.

METHODS

99 patients (52 men and 47 women) with a diagnosis of primary open-angle glaucoma were examined. The comparison group consisted of 100 people (81 women and 19 men). TLR2 (rs5743708), TLR3 (rs3775291), TLR4 (rs4986790, rs4986791) and TLR6 (rs5743810) polymorphisms were analyzed by RT-PCR using test systems with Syber Green (Lytex, Russia). Statistical analysis was performed using the software package SPSS 23.0 and Arlequin 3.5.2.2.

RESULTS

the distribution of genotypes in the patient group and in the control group corresponded to the Hardy-Weinberg equilibrium. The genotype frequencies did not significantly differ between the two analyzed groups. The frequency of TLR2-753 ArgArg:TLR6-249 ProPro was increased in the group of patients with POAG. The linkage disequilibrium between two polymorphic positions of the TLR4 gene was revealed. In addition, the linkage disequilibrium between TLR2-TLR6 gene for the glaucoma group and the control group was revealed.

CONCLUSION

an increase in certain genotypes in the patient group relative to the control group may indirectly indicate the involvement of infectious factors in the initiation of POAG. However, despite the proven importance of the participation of their protein products in the pathogenesis of glaucoma, the relationship of TLR polymorphism requires additional research taking into account the ethnic characteristics of patients and intergenic interactions for a better understanding of the complex mechanisms of disease development. This will help carry out early diagnosis and develop the necessary therapeutic strategy.

Human immune system: Exploring diversity across individuals and populations

The immune response is an intricate system that involves the complex connection of cellular and molecular components, each with distinct functional specialisations. It has a distinct capacity to adjust and mould the immune response in accordance with specific stimuli, influenced by both genetic and environmental factors. The presence of genetic diversity, particularly across different ethnic and racial groups, significantly contributes to the impact of incidence of diseases, disease susceptibility, autoimmune disorders, and cancer risks in specific regions and certain populations. Environmental factors, including geography and socioeconomic status, further modulate the variety of the immune system responses. These, in turn, affect the susceptibility to infectious diseases and development of autoimmune disorders. Despite the complexity of the relationship, there remains a gap in understanding the specificity of immune indices across races, immune reference ranges among populations, highlighting the need for deeper understanding of immune diversity for personalized approaches in diagnostics and therapeutics. This review systematically organizes these findings, with the goal of emphasizing the potential of targeted interventions to address health disparities and advance translational research, enabling a more comprehensive strategy. This approach promises significant advancements in identifying specific immunological conditions, focusing on personalized interventions, through both genetic and environmental factors.

Screening the effective components of Lysionotus pauciflorus Maxim. on the treatment of LPS induced acute lung injury mice by integrated UHPLC-Q-TOF-MS/MS and network pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

Acute lung injury (ALI) is an inflammatory reaction produced through various injury-causing factors acting on the lungs in a direct or indirect way, with a high morbidity and mortality rate. A review of clinical experience has revealed that Lysionotus pauciflorus Maxim (LP) has a significant therapeutic effect on ALI. However, the comprehensive effective components of LP are uncertain, and the mechanisms, especially the potential therapeutic target for anti-ALI, are still unknown.

AIMS OF THE STUDY

In vitro and in vivo validation of the pharmacodynamics of LP in the treatment of ALI and exploration of its potential mechanism of action based on network pharmacology, molecular docking and experimental validation.

MATERIALS AND METHODS

Ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS) was employed to identify the ingredients of LP extracts. The potential bioactive ingredients, key targets and signalling pathways were identified by network pharmacology, based on the results of the mass spectrometry analysis. Subsequently, molecular docking was performed on the screened core components and key targets to calculate their molecular binding energies and binding potentials, and to explore the mutual binding modes of small-molecule ligands and large-molecule proteins. Finally, lipopolysaccharide (LPS)-induced RAW264.7 cell model and ALI mice model were used to validate the therapeutic effects and potential mechanism of LP extract towards ALI.

RESULTS

From the mass spectrometry results of LP extracts, a total of 89 chemical components were identified, including 46 phenylethanol glycosides, 26 flavonoids, 9 organic acids and their derivatives and 8 other compounds. And furthermore 39 core active components were screened by network pharmacology. The top 10 core components (4 phenylethanol glycosides, 6 flavonoids) have been screened in the composition -target-disease network, and 37 core targets related to LP efficacy were obtained by fitting PPI network analysis. 10 signalling pathways and their targets associated with LP treatment of ALI were obtained by GO/KEGG analysis, indicating that LP could regulate TLR4 and NF-κB signalling pathways through 4 key targets, namely NFKB1, RELA, TLR4 and TNF. The results of the molecular docking procedure indicated a strong affinity, with the binding energies between each component and the target site being less than -6 kcal/mol. The binding modes included Hydrogen Bonds, Pi-Pi interaction, Hydrophobic Interactions, Salt Bridges, Pi-cation interactions. These observations were subsequently validated in vitro and in vivo experiments. The outcomes of in vitro and in vivo experiments demonstrated that LP was effective in reducing the infiltration of inflammatory bacteria in lung tissues and attenuated the expression of pro-inflammatory cytokines in LPS-stimulated mice bronchoalveolar lavage fluid (BALF) and RAW264.7 cells. Furthermore, LP inhibited the expression and phosphorylation of TLR4 protein and NF-κB protein, thus playing a role in the prevention of ALI.

CONCLUSIONS

In this study, mass spectrometry analysis was combined with biomolecular networks to initially elucidate the potential of LP to treat ALI by modulating the TLR4/NF-κB pathway. This offers a definitive experimental basis for the development of new LP drugs.

Perilla frutescens leaf extracts alleviate acute lung injury in mice by inhibiting KAT2A

ETHNOPHARMACOLOGICAL RELEVANCE

Acute lung injury (ALI) can lead to respiratory failure and even death. KAT2A is a key target to suppress the development of inflammation. A herb, perilla frutescens, is an effective treatment for pulmonary inflammatory diseases with anti-inflammatory effects; however, its mechanism of action remains unclear.

AIM OF THE STUDY

The purpose of this study was to investigate the therapeutic effect and underlying mechanism of perilla frutescens leaf extracts (PLE), in the treatment of ALI by focusing on its ability to treat inflammation.

MATERIALS AND METHODS

In vivo and in vitro models of ALI induced by LPS. Respiratory function, histopathological changes of lung, and BEAS-2B cells damage were assessed upon PLE. This effect is also tested under conditions of KAT2A over expression and KAT2A silencing.

RESULTS

PLE significantly attenuated LPS-induced histopathological changes in the lungs, improved respiratory function, and increased survival rate from LPS stimuation background in mice. PLE remarkably suppressed the phosphorylation of STAT3, AKT, ERK (1/2) and the release of cytokines (IL-6, TNF-α, and IL-1β) induced by LPS via inhibiting the expression of KAT2A.

CONCLUSIONS

PLE has a dose-dependent anti-inflammatory effect by inhibiting KAT2A expression to suppress LPS-induced ALI n mice. Our study expands the clinical indications of the traditional medicine PLE and provide a theoretical basis for clinical use of acute lung injury.

Toll-like receptor 4 - a multifunctional virus recognition receptor

Since the initial description of Toll receptors in Drosophila and their mammalian counterparts Toll-like receptors (TLRs), numerous fundamental and applied studies have explored their crucial role as sensors of pathogen-associated molecular patterns (PAMPs). Among the ten human TLRs, TLR4 is particularly well known for its ability to detect lipopolysaccharides (LPS), a component of the Gram-negative bacterial cell wall. In addition to its archetypal functions, TLR4 is also a versatile virus sensor. This review provides a background on the discovery of TLR4 and how this knowledge laid a foundation for characterization of its diverse roles in antiviral responses, examined through genetic, biochemical, structural, and immunological approaches. These advances have led to a deeper understanding of the molecular functions that enable TLR4 to orchestrate multi-nodal control by professional antigen-presenting cells (APCs) to initiate appropriate and regulated antiviral immune responses.

Inherent immunity and adaptive immunity: Mechanism and role in AECOPD

Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is the leading cause of hospitalization and mortality in COPD patients. The occurrence of antibiotic resistance and the progression of non-infectious diseases contribute to poor patient outcomes. Thus, a comprehensive understanding of the mechanisms underlying AECOPD is essential for effective prevention. It is widely acknowledged that the immune system plays a fundamental role in pathogen clearance and the development of inflammation. Immune dysregulation, either due to deficiency or hyperactivity, has been implicated in AECOPD pathogenesis. Therefore, the purpose of this review is to investigate the possible mechanisms underlying dysregulated immune function and disease progression in COPD patients, specifically focusing on the innate and adaptive immune responses. The ultimate aim is to provide new insights for clinical prevention and treatment strategies targeting AECOPD.

Single Nucleotide Polymorphisms on Toll-like Receptor-4 and the Risk of Developing Skin Cancer

Exposure to solar ultraviolet (UV) radiation is an established risk factor for skin cancer. Toll-like receptor-4 (TLR4)-mediated immune dysregulation has emerged as a key mechanism for the detrimental effects of acute and chronic UV exposure and skin cancer in mice. Single nucleotide polymorphisms (SNPs) on the TLR4 gene have been reported to increase or decrease susceptibility to various cancers in other organs. There is limited information on TLR4 SNPs and susceptibility to human keratinocyte carcinomas. The study's objective is to test the association between TLR4 SNPs and the risk of developing keratinocyte carcinomas. Skin cancer patients and controls at the University of Alabama at Birmingham completed a cross-sectional survey on personal and family history of skin cancer as well as on sunscreen use and tanning proneness. Peripheral blood samples were obtained from participants, and DNA was extracted to genotype the TLR4 SNPs. Descriptive analytics were used to describe the cohort. Multivariable logistic regression models were used to assess the association between TLR4 SNPs and skin cancer risk. The sample consisted of a cohort of 93 skin cancer patients over the age of 50 and 94 controls; 33.3% of cases and 44.7% of controls were females; 12.9% of cases and 17% of controls had a TLR4 SNP. The most common SNP was D299G/T399I in 9.7% of skin cancer patients and 13.8% of controls. We did not find a statistically significant association between the D299G/T399I SNP and skin cancer (odds ratio (OR) = 0.34, 95% CI: 0.11, 1.07, p = 0.065) adjusting for age, sex, eye color, actinic keratosis, sunscreen use and reapplication, and family history of skin cancer. Based on our findings from our limited cohort of participants, we found some protective effect for the TLR4 SNP for skin cancer, which was not statistically significant. Validation of these findings in a larger cohort is warranted.

Gut microbes, diet, and genetics as drivers of metabolic liver disease: a narrative review outlining implications for precision medicine

Metabolic dysfunction-associated steatotic liver disease (MASLD) is rapidly increasing in prevalence, impacting over a third of the global population. The advanced form of MASLD, Metabolic dysfunction-associated steatohepatitis (MASH), is on track to become the number one indication for liver transplant. FDA-approved pharmacological agents are limited for MASH, despite over 400 ongoing clinical trials, with only a single drug (resmetirom) currently on the market. This is likely due to the heterogeneous nature of disease pathophysiology, which involves interactions between highly individualized genetic and environmental factors. To apply precision medicine approaches that overcome interpersonal variability, in-depth insights into interactions between genetics, nutrition, and the gut microbiome are needed, given that each have emerged as dynamic contributors to MASLD and MASH pathogenesis. Here, we discuss the associations and molecular underpinnings of several of these factors individually and outline their interactions in the context of both patient-based studies and preclinical animal model systems. Finally, we highlight gaps in knowledge that will require further investigation to aid in successfully implementing precision medicine to prevent and alleviate MASLD and MASH.

Allelic, Genotypic, and Haplotypic Analysis of Cytokine IL17A, IL17F, and Toll-like Receptor TLR4 Gene Polymorphisms in Metabolic-Dysfunction-Associated Steatotic Liver Disease: Insights from an Exploratory Study

(1) Background: Interleukin 17 (IL17) and toll-like receptor 4 (TLR4) elevate the risk of metabolic and liver diseases. (2) Methods: This study's objective was to explore the association of IL17 and TLR4 gene polymorphisms with MASLD susceptibility and test their effect on serum IL17 and TLR4 levels. A total of 43 patients with MASLD (MASH/MAFL) and 38 healthy individuals were genotyped for IL17F-A7488G, IL17A-G197A, TLR4-Asp299Gly, and TLR4-Thr399Ile polymorphisms using PCR-RFLP. ELISA methods determined IL17F, IL17A, and TLR4 serum levels. (3) Conclusions: Patients carrying the variant genotypes (A/G + G/G) of IL17-A7448G (OR = 5.25), (G/A + A/A) of IL17-G197A (OR = 10.57), (Asp/Gly + Gly/Gly) of TLR4-Asp299Gly (OR = 3.52), or (Thr/Ile + Ile/Ile) of TLR4-Thr399Ile (OR = 9.87) had significantly increased odds of MASH. Genotype (G/A + A/A) of IL17-G197A was significantly associated with the odds of MAFL (p = 0.0166). Allele A of the IL17-G197A polymorphism was significantly related to increased odds of MAFL (OR = 4.13, p = 0.0133). In contrast, allele A of IL17-G197A (OR = 5.41, p = 0.008), allele Gly of TLR4-Asp299Gly (OR = 3.19, p = 0.046), and allele Ile of TLR4-Thr399Ile (OR = 6.94, p = 0.008) polymorphisms were significantly related to an increased risk of MASH. Allele A of IL17A-G197A, allele Gly of TLR4-Asp299Gly, and allele Ile of TLR4-Thr399Ile gene polymorphisms were significantly associated with the increased odds of MASLD. In patients with MASLD, we found significant influence from the IL17A-G197A gene polymorphism on IL17F levels (p = 0.0343).

Comparative Analysis of Intestinal TLR4 Gene Expression and Functional Verification in Lepus yarkandensis and Oryctolagus cuniculus

Lepus yarkandensis live year-round in harsh desert environments and are less susceptible to enteritis. The living conditions of Oryctolagus cuniculus in captivity were suitable, but they were highly susceptible to death by Gram-negative bacteria infected with inflammatory bowel disease complex.TLR4 is closely related to the occurrence of enteritis, and the neighbor-joining topology based on the 12S rDNA sequences showed that the relationship between O. cuniculus and L. yarkandensis is as high as 98%.Therefore, we chose O. cuniculus and L. yarkandensis for comparative study.The purpose of this study was to investigate the role of Toll-like receptor 4 (TLR4) in the regulation of immunity and inflammation in the intestinal tract of L. yarkandensis. In this study, the TLR4 gene was cloned for the first time in the colon of L. yarkandensis. The expression of TLR4 in the intestinal tissues of L. yarkandensis and O. cuniculus was detected by histological observation, real-time fluorescence quantification PCR(qRT-PCR), and protein blotting (Western blot).An LPS-induced cell inflammation model was constructed in vitro, and ELISA was used to examine the effect of pEGFP-N1-TLR4 and siRNA knockout on the anti-inflammatory ability of the TLR4 gene. The results showed that the open reading frame of the L. yarkandensis TLR4 gene was 2520 bp in length. Compared with the sequence of O. cuniculus, there were 15 differences in the TLR4 amino acid sequence of L. yarkandensis, 12 of which occurred in the LRR domain and 2 in the TIR domain, and the sequence changed from G to D at position 298. Immunohistochemistry showed that TLR4 was mainly expressed in the epithelial cells of the colon L. yarkandensis, and the expression level of TLR4 in the cecum and colon was significantly lower compared with that of O. cuniculus. qRT-PCR and Western blot results showed that the expression level of TLR4 in the colon of L. yarkandensis was significantly lower than that of O. cuniculus. At the cellular level, ELISA showed that overexpression of the TLR4 protein in L. yarkandensis could reduce the LPS-induced inflammatory response. Therefore, according to the above results, the protein structure and function of L. yarkandensis TLR4 may be different due to the change of nucleotide, which affects its binding with LPS and the activation of downstream molecules, so that L. yarkandensis is not prone to enteritis and can adapt to the harsh desert environment for a long time. This study also laid the foundation for improving the disease resistance of O. cuniculus and promoting the development and utilization of genes in L. yarkandensis.

Toll-Like Receptor Genes and Risk of Latent Tuberculosis Infection in People Infected with HIV-1

The purpose of this study was to determine the contribution of genetic factors, i.e., the level of expression and polymorphisms of Toll-like receptors (TLR), to the susceptibility of latent tuberculosis infection in a Russian cohort of individuals infected with HIV. The patients (n = 317) with confirmed HIV infection were divided into two groups according to the results of the STANDARD E TB-Feron test: 63 cases with a latent TB infection and 274 controls without LTBI. Total DNA and RNA were isolated from whole-blood samples. SNP genotyping and expression levels of five TLR genes (TLR1, TLR2, TLR4, TLR6, and TLR8) were determined by means of real-time PCR. There were no significant differences in the expression levels of the TLRs between the case and control groups. In addition, we did not observe any significant association between the analyzed SNPs and the susceptibility of Latent tuberculosis infection (LTBI) in patients with HIV. However, patients from an entire cohort with the rs4986790-GG (TLR4) and rs5743708-GG (TLR2) genotypes were characterized by lower CD4 T-cell counts compared to carriers of alternative alleles. Moreover, we found a significant risk of a hazardous drop in the CD4 T-cell count below 350 cells/mm3 associated with the rs4986790-G (TLR4) allele. Latent tuberculosis infection in individuals infected with HIV does not significantly modify the level of TLR gene expression.

Respiratory Diseases Associated With Organic Dust Exposure

Organic dusts are complex bioaerosol mixtures comprised of dust and par ticulate matter of organic origin. These include components from bacteria, fungi, pollen, and viruses to fragments of animals and plants commonplace to several environmental/occupational settings encompassing agriculture/farming, grain processing, waste/recycling, textile, cotton, woodworking, bird breeding, and more. Organic dust exposures are linked to development of chronic bronchitis, chronic obstructive pulmonary disease, asthma, asthma-like syndrome, byssinosis, hypersensitivity pneumonitis, and idiopathic pulmonary fibrosis. Risk factors of disease development include cumulative dust exposure, smoking, atopy, timing/duration, and nutritional factors. The immunopathogenesis predominantly involves Toll-like receptor signaling cascade, T-helper 1/T-helper 17 lymphocyte responses, neutrophil influx, and potentiation of manifestations associated with allergy. The true prevalence of airway disease directly attributed to organic dust, especially in a workplace setting, remains challenging. Diagnostic confirmation can be difficult and complicated by hesitancy from workers to seek medical care, driven by fears of potential labor-related consequence. Clinical respiratory and systemic presentations coupled with allergy testing, lung function patterns of obstructive versus restrictive disease, and radiological characteristics are typically utilized to delineate these various organic dust-associated respiratory diseases. Prevention, risk reduction, and management primarily focus on reducing exposure to the offending dust, managing symptoms, and preventing disease progression.

TLR4 Polymorphisms (T399I/D299G) Association with Schizophrenia and Bipolar Disorder in a Tunisian Population

Immune dysregulation has been widely described in the pathophysiology of schizophrenia (SCZ) and bipolar disorder (BD). Particularly, TLR4-altered activation was proposed as one of the underlying processes of psychosis onset. Since TLR4 activation was altered by T399I and D299G polymorphisms, we hypothesized that those variants could present common genetic factors of SCZ and BD. A total of 293 healthy volunteers and 335 psychotic patients were genotyped using PCR-RFLP. Genotype, allele, and haplotype distribution between controls and patients were evaluated according to clinical parameters. Statistical analyses were adjusted by logistic regression. In dominant model, T399I CT + TT and allele frequency were significantly higher in controls compared to psychotic population (p = 0.004, p = 0.002, respectively), SCZ (p = 0.02, p = 0.01, respectively), and BD (p = 0.03, p = 0.02, respectively). Similarly, D299G AG + GG and allele frequency were significantly higher in controls compared to psychotic population (p = 0.04, p = 0.04, respectively) and SCZ (p = 0.04, p = 0.03, respectively). T399I CT + TT and T allele were overrepresented in controls compared to paranoid subgroup (Padjusted = 0.04, p = 0.04, respectively) and type I BD (p = 0.04). Moreover, T399I and D299G were less prevalent in SCZ late-onset age (p = 0.03, p = 0.02, respectively). TA haplotype was associated with protection from psychoses (p = 0.02) and particularly from schizophrenia (p = 0.04). In conclusion, TLR4 polymorphisms could present a preventive genetic background against psychoses onset in a Tunisian population. While T399I could be associated with protection against SCZ and BD, presenting an overlapping genetic factor between those psychoses, D299G was suggested to be associated with protection only from schizophrenia.

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.

Diffusely distributed centrilobular micronodules and branching opacities as the main chest computed tomography manifestations in a patient with humidifier lung

We report a 60-year-old man with humidifier lung showing diffusely distributed centrilobular micronodules and branching opacities on chest computed tomography (CT). Fever and dyspnea occurred 2 months after using an ultrasonic humidifier. KL-6 and SP-D were within normal ranges. Bronchoalveolar lavage showed elevated lymphocytes (53 %) and histological findings of transbronchial lung biopsy demonstrated organizing pneumonia. His condition improved after cessation of the humidifier. A provocation test exhibited a positive response to the humidifier. Humidifier lung should be considered as a differential diagnosis in patients with these CT findings. Detailed clinical, pathological and microbiological examinations are needed to exclude other diseases.

The role of Toll-like receptors in neuropsychiatric disorders: Immunopathology, treatment, and management

Neuropsychiatric disorders denote a broad range of illnesses involving neurology and psychiatry. These disorders include depressive disorders, anxiety, schizophrenia, bipolar disorder, attention deficit hyperactivity disorder, autism spectrum disorders, headaches, and epilepsy. In addition to their main neuropathology that lies in the central nervous system (CNS), lately, studies have highlighted the role of immunity and neuroinflammation in neuropsychiatric disorders. Toll-like receptors (TLRs) are innate receptors that act as a bridge between the innate and adaptive immune systems via adaptor proteins (e.g., MYD88) and downstream elements; TLRs are classified into 13 families that are involved in normal function and illnesses of the CNS. TLRs expression affects the course of neuropsychiatric disorders, and is influenced during their pharmacotherapy; For example, the expression of multiple TLRs is normalized during the major depressive disorder pharmacotherapy. Here, the role of TLRs in neuroimmunology, treatment, and management of neuropsychiatric disorders is discussed. We recommend longitudinal studies to comparatively assess the cell-type-specific expression of TLRs during treatment, illness progression, and remission. Also, further research should explore molecular insights into TLRs regulation and related pathways.

HLA gene variations and mycotoxin toxicity: Four case reports

Mycotoxins are produced by certain molds that can cause many health effects. We present four human cases of prolonged consistent mycotoxins exposure linked to genetic variations in human leukocyte antigen (HLA) alleles. The HLA-DR/DQ isotype alleles are linked to mycotoxins susceptibility due to the lack of proper immune response; individuals with these alleles are poor eliminators of mycotoxins from their system. Four subjects with variations in their HLA-DR alleles were exposed to mycotoxins from living in mold-infested houses and experienced persistent mold-related symptoms long after moving out from the mold-infested houses and only exposed to the levels of molds found in the ambient air. From one of the subjects, two urine samples were collected ~ 18 months apart after the cessation of exposure. Urinary elimination rate was extremely slow for two of the mycotoxins (ochratoxin A [OTA] and mycophenolic acid [MPA]) detected in both samples. In 18 months, decline in OTA level was only ~ 3-fold (estimated t½ of ~ 311 days) and decline in MPA level was ~ 11-fold (estimated t½ of ~ 160 days), which was ~ 10- and ~ 213-fold slower than expected in individuals without HLA-DR alleles, respectively. We estimated that ~ 4.3 and ~ 2.2 years will be required for OTA and MPA to reach < LLQ in urine, respectively. Three other subjects with variations in HLA-DR alleles were members of a family who lived in a mold-infested house for 4 years. They kept experiencing mold-related issues >2 years after moving to a non-mold-infested house. Consistent exposure was confirmed by the presence of several mycotoxins in urine >2 years after the secession of higher than background (from outdoor ambient air) exposure. This was consistent with the extremely slow elimination of mycotoxins from their system. Variations in HLA-DR alleles can, consequently, make even short periods of exposure to chronic exposure scenarios with related adverse health effects. It is, therefore, important to determine genetic predisposition as a reason for prolonged/lingering mold-related symptoms long after the cessation of higher than background exposure. Increased human exposure to mycotoxins is expected from increased mold infestation that is anticipated due to rising CO2, temperature, and humidity from the climate change with possibly increased adverse health effects, especially in individuals with genetic susceptibility to mold toxicity.

Variant rs4986790 of toll-like receptor 4 affects the signaling and induces cell dysfunction in patients with severe COVID-19

OBJECTIVES

We investigated the expression of toll-like receptor (TLR)-4 on the cell surface of innate and adaptive cells from patients with COVID-19 carrying the rs4986790 GG genotype in the TLR4 gene and the functional profile of these cells.

METHODS

We included 1169 hospitalized patients with COVID-19. The rs4986790 in TLR4 was identified by real-time polymerase chain reaction. Peripheral blood mononuclear cells were isolated and cultured to evaluate TLR-4 expression on immune cells. Supernatants recovered culture assays were stored, and we measured cytokines and cytotoxic molecules.

RESULTS

We showed that the rs4986790 (GG) was significantly associated (P = 0.0310) with severe COVID-19. Cells of patients with COVID-19 carrying the GG genotype have increased the frequency of monocytes and activated naïve and non-switched B cells positive to TLR-4 when cells are stimulated with lipopolysaccharide and with spike protein of SARS-CoV-2. Also, cells from patients with GG COVID-19 cannot produce pro-inflammatory cytokines after lipopolysaccharide stimulus, but they are high producers of cytotoxic molecules at baseline.

CONCLUSIONS

The rs4986790 GG genotype of the TLR4 is associated with the risk of COVID-19 and acute respiratory distress syndrome. Peripheral blood mononuclear cells of patients carrying the rs4986790 (TLR4) GG genotype had a limited delivery of pro-inflammatory cytokines compared to the AA and AG genotypes in which TLR-4 stimulation induces IL-10, IL-6, tumor necrosis factor-α, and Fas ligand production.

Frequency of toll-like receptor 4 variants and association with treatment response in children with primary immune thrombocytopenia

OBJECTIVES

To investigate the frequency of toll-like receptor 4 (TLR4) variants c.896A>G (p.Asp299Gly) and c.1196C>T (p.Thr399Ile) among Egyptian children with primary immune thrombocytopenia (pITP), and their association with disease course and response to treatment.

METHODS

A case-control study that included 80 children with pITP and 50 age- and sex-matched healthy controls. TLR4 c.896A>G and c.1196C>T variants were genotyped using polymerase chain reaction-restriction fragment length polymorphism. Patients were classified according to their response to treatment after 3 months as responders and nonresponders.

RESULTS

Compared with controls, children with pITP had significantly higher minor allele frequencies of TLR4 p.Asp299Gly (16.25% vs. 6%, odds ratio [OR] 3.04, 95% confidence interval [CI]: 1.16-9.36, p = .014) and p.Thr399Ile (20% vs. 4%, OR 6, 95% CI: 2.02-24.01, p < .001). The presence of p.Asp299Gly variant was significantly associated with chronic ITP (OR 7.78, 95% CI: 2.04-35.69, p < .001) and non-response to therapy with steroid (OR 11.67, 95% CI: 1.32-104.08, p = .012), but not thrombopoietin-receptor agonist (OR 1.67, 95% CI: 0.35-8.19, p = .464). Likewise, having p.Thr399Ile variant was significantly associated with chronic ITP (OR 5.14, 95% CI: 1.6-17.4, p = .002) and non-response to therapy with steroid (OR 6.1, 95% CI: 1.01-49.06, p = .046) but not thrombopoietin-receptor agonist (OR 1.57, 95% CI: 0.33-7.58, p = .515).

CONCLUSION

The presence of TLR4 p.Asp299Gly or p.Thr399Ile variant may be associated with ITP predisposition, chronicity, and non-response to upfront steroid therapy. These findings enhance our understanding of the complex pathophysiology of pITP with potentially important clinical implications.

M2a macrophages facilitate resolution of chemically-induced colitis in TLR4-SNP mice

IMPORTANCE

Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, impacts millions of individuals worldwide and severely impairs the quality of life for patients. Dysregulation of innate immune signaling pathways reduces barrier function and exacerbates disease progression. Macrophage (Mφ) signaling pathways are potential targets for IBD therapies. While multiple treatments are available for IBD, (i) not all patients respond, (ii) responses may diminish over time, and (iii) treatments often have undesirable side effects. Genetic studies have shown that the inheritance of two co-segregating SNPs expressed in the innate immune receptor, TLR4, is associated with human IBD. Mice expressing homologous SNPs ("TLR4-SNP" mice) exhibited more severe colitis than WT mice in a DSS-induced colonic inflammation/repair model. We identified a critical role for M2a "tissue repair" Mφ in the resolution of colitis. Our findings provide insight into potential development of novel therapies targeting Mφ signaling pathways that aim to alleviate the debilitating symptoms experienced by individuals with IBD.

A small-molecule TLR4 antagonist reduced neuroinflammation in female E4FAD mice

BACKGROUND

APOE genotype is the greatest genetic risk factor for sporadic Alzheimer's disease (AD). APOE4 increases AD risk up to 12-fold compared to APOE3, an effect that is greater in females. Evidence suggests that one-way APOE could modulate AD risk and progression through neuroinflammation. Indeed, APOE4 is associated with higher glial activation and cytokine levels in AD patients and mice. Therefore, identifying pathways that contribute to APOE4-associated neuroinflammation is an important approach for understanding and treating AD. Human and in vivo evidence suggests that TLR4, one of the key receptors involved in the innate immune system, could be involved in APOE-modulated neuroinflammation. Consistent with that idea, we previously demonstrated that the TLR4 antagonist IAXO-101 can reduce LPS- and Aβ-induced cytokine secretion in APOE4 glial cultures. Therefore, the goal of this study was to advance these findings and determine whether IAXO-101 can modulate neuroinflammation, Aβ pathology, and behavior in mice that express APOE4.

METHODS

We used mice that express five familial AD mutations and human APOE3 (E3FAD) or APOE4 (E4FAD). Female and male E4FAD mice and female E3FAD mice were treated with vehicle or IAXO-101 in two treatment paradigms: prevention from 4 to 6 months of age or reversal from 6 to 7 months of age. Learning and memory were assessed by modified Morris water maze. Aβ deposition, fibrillar amyloid deposition, astrogliosis, and microgliosis were assessed by immunohistochemistry. Soluble levels of Aβ and apoE, insoluble levels of apoE and Aβ, and IL-1β were measured by ELISA.

RESULTS

IAXO-101 treatment resulted in lower Iba-1 coverage, lower number of reactive microglia, and improved memory in female E4FAD mice in both prevention and reversal paradigms. IAXO-101-treated male E4FAD mice also had lower Iba-1 coverage and reactivity in the RVS paradigm, but there was no effect on behavior. There was also no effect of IAXO-101 treatment on neuroinflammation and behavior in female E3FAD mice.

CONCLUSION

Our data supports that TLR4 is a potential mechanistic therapeutic target for modulating neuroinflammation and cognition in APOE4 females.

Polymorphisms in Toll-Like receptors genes and their associations with immunological parameters in Plasmodium vivax malaria in the Brazil-French Guiana Border

BACKGROUND

The innate immune response plays an important role during malaria. Toll-like receptors (TLR) are capable of recognizing pathogen molecules. We aimed to evaluate five polymorphisms in TLR-4, TLR-6, and TLR-9 genes and their association with cytokine levels and clinical parameters in malaria from the Brazil-French Guiana border.

METHODS

A case-control study was conducted in Amapá, Brazil. P. vivax patients and individuals not infected were evaluated. Genotyping of five SNPs was carried out by qPCR. Circulating cytokines were measured by CBA. The MSP-119 IgG antibodies were performed by ELISA.

RESULTS

An association between TLR4 A299G with parasitemia was observed. There was an increase for IFN-ɤ, TNF-ɑ, IL-6, and IL-10 in the TLR-4 A299G and T3911, TLR-6 S249P, and TLR-9 1486C/T, SNPs for the studied malarial groups. There were significant findings for the TLR-4 variants A299G and T3911, TLR-9 1237C/T, and 1486C/T. For the reactivity of MSP-119 antibodies levels, no significant results were found in malaria, and control groups.

CONCLUSIONS

The profile of the immune response observed by polymorphisms in TLRs genes does not seem to be standard for all types of malaria infection around the world. This can depend on the human population and the species of Plasmodium.

Infection, Inflammation, and Immunity in Sepsis

Sepsis is triggered by microbial infection, injury, or even major surgery. Both innate and adaptive immune systems are involved in its pathogenesis. Cytoplasmic presence of DNA or RNA of the invading organisms or damaged nuclear material (in the form of micronucleus in the cytoplasm) in the host cell need to be eliminated by various nucleases; failure to do so leads to the triggering of inflammation by the cellular cGAS-STING system, which induces the release of IL-6, TNF-α, and IFNs. These cytokines activate phospholipase A2 (PLA2), leading to the release of polyunsaturated fatty acids (PUFAs), gamma-linolenic acid (GLA), arachidonic acid (AA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA), which form precursors to various pro- and anti-inflammatory eicosanoids. On the other hand, corticosteroids inhibit PLA2 activity and, thus, suppress the release of GLA, AA, EPA, and DHA. PUFAs and their metabolites have a negative regulatory action on the cGAS-STING pathway and, thus, suppress the inflammatory process and initiate inflammation resolution. Pro-inflammatory cytokines and corticosteroids (corticosteroids > IL-6, TNF-α) suppress desaturases, which results in decreased formation of GLA, AA, and other PUFAs from the dietary essential fatty acids (EFAs). A deficiency of GLA, AA, EPA, and DHA results in decreased production of anti-inflammatory eicosanoids and failure to suppress the cGAS-STING system. This results in the continuation of the inflammatory process. Thus, altered concentrations of PUFAs and their metabolites, and failure to suppress the cGAS-STING system at an appropriate time, leads to the onset of sepsis. Similar abnormalities are also seen in radiation-induced inflammation. These results imply that timely administration of GLA, AA, EPA, and DHA, in combination with corticosteroids and anti-IL-6 and anti-TNF-α antibodies, may be of benefit in mitigating radiation-induced damage and sepsis.

Association of Toll-Like Receptor Gene Polymorphisms with Tuberculosis in HIV-Positive Participants

Genetic factors in the HIV-background may play a significant role in the susceptibility to secondary diseases, like tuberculosis, which is the leading cause in mortality of HIV-positive people. Toll-like receptors (TLRs) are considered to be receptors for adaptive immunity, and polymorphisms in TLR genes can influence the activity of the immune response to infection. We conducted a case-control study of the association of TLR gene polymorphisms with the risk of tuberculosis coinfection in a multi-country sample of HIV-positive participants. Our study revealed certain associations between TLR4 and TLR6 polymorphisms and HIV-tuberculosis coinfection. We also found that the analyzed TLR1 and TLR4 polymorphisms were linked with the decline in CD4+ cell count, which is a predictor of disease progression in HIV-infected individuals. Our findings confirm that TLR gene polymorphisms are factors that may contribute to development of HIV-tuberculosis coinfection. However, the essence of the observed associations remains unclear, since it can also include both environmental factors and epigenetic mechanisms of gene expression regulation.

Pathomorphological Manifestations and the Course of the Cervical Cancer Disease Determined by Variations in the TLR4 Gene

Cervical cancer (CC) is often associated with human papillomavirus (HPV). Chronic inflammation has been described as one of the triggers of cancer. The immune system fights diseases, including cancer. The genetic polymorphism of pathogen recognition receptors potentially influences the infectious process, development, and disease progression. Many candidate genes SNPs have been contradictory demonstrated to be associated with cervical cancer by association studies, GWAS. TLR4 gene activation can promote antitumor immunity. It can also result in immunosuppression and tumor growth. Our study aimed to investigate eight selected polymorphisms of the TLR4 gene (rs10759932, rs1927906, rs11536898, rs11536865, rs10983755, rs4986790, rs4986791, rs11536897) and to determine the impact of polymorphisms in genotypes and alleles on the pathomorphological characteristics and progression in a group of 172 cervical cancer subjects with stage I-IV. Genotyping was performed by RT-PCR assay. We detected that the CA genotype and A allele of rs11536898 were significantly more frequent in patients with metastases (p = 0.026; p = 0.008). The multivariate logistic regression analysis confirmed this link to be significant. The effect of rs10759932 and rs11536898 on progression-free survival (PFS) and overall survival (OS) has been identified as important. In univariate and multivariate Cox analyses, AA genotype of rs11536898 was a negative prognostic factor for PFS (p = 0.024; p = 0.057, respectively) and OS (p = 0.008; p = 0.042, respectively). Rs11536898 C allele predisposed for longer PFS (univariate and multivariate: p = 0.025; p = 0.048, respectively) and for better OS (univariate and multivariate: p = 0.010; p = 0.043). The worse prognostic factor of rs10759932 in a univariate and multivariate Cox analysis for survival was CC genotype: shorter PFS (p = 0.032) and increased risk of death (p = 0.048; p = 0.015, respectively). The T allele of rs10759932 increased longer PFS (univariate and multivariate: p = 0.048; p = 0.019, respectively) and longer OS (univariate and multivariate: p = 0.037; p = 0.009, respectively). Our study suggests that SNPs rs10759932 and rs11536898 may have the potential to be markers contributing to the assessment of the cervical cancer prognosis. Further studies, preferably with larger groups of different ethnic backgrounds, are needed to confirm the results of the current study.

Lessons from Dairy Farmers for Occupational Allergy and Respiratory Disease

PURPOSE OF REVIEW

Exposure to bioaerosols at dairies has long been associated with allergy, respiratory disease, and decreases in lung function. Recent advancements in exposure assessments have aided our understanding on the size distribution and composition of these bioaerosols, but investigations focusing solely on exposures may overlook important intrinsic factors impacting worker's susceptibility to disease.

RECENT FINDINGS

In our review, we discuss the most recent studies examining the exposures and genetic factors that contribute to occupational disease in dairy work. We also review more recent concerns in livestock work associated with zoonotic pathogens, antimicrobial resistant genes, and the role of the human microbiome. The studies highlighted in this review demonstrate the need for further research to better understand bioaerosol exposure-response relationships in the context of extrinsic and intrinsic factors, antibiotic-resistant genes, viral pathogens, and the human microbiome to help inform effective interventions that improve respiratory health among dairy farmers.

The pathogenic effect of SNPs on structure and function of human TLR4 using a computational approach

The human toll-like receptor (hTLR) 4 single nucleotide polymorphisms (SNPs) are interconnected with cancer, multiple genetic disorders and other immune-related diseases. The detrimental effect of SNPs in hTLR4 with respect to structure and function has not been explored in depth. The present study concatenates the biological consequences of the SNPs along with structural modifications predicted at the hTLR4 gene. A total of 7910 SNPs of hTLR4 were screened, and 21 damage-causing SNPs were identified. Out of 21, seven are present in the extracellular region, of which three were detected as deleterious and the fourth one as moderate. These three mutations are located in a highly conserved region and influence conformational change. The change leads to the widening of the Leucine-rich repeat (LRR) arc to a maximum of 16.9 Å and a minimum of 8.7 Å. Expansion/shortening of LRR arc, never discussed before, would cause loss of myeloid differentiation factor 2 (MD-2) interactions in the interior and diminish lipopolysaccharide (LPS) responses. Similarly, in all mutant structures, the binding region for HMGB1 and LPS is deflating or in an unsupportive conformation. Thus, SNPs affect the regular signaling cascade and might result in human sepsis, genetic disorders, cancer and other immunological related diseases.Communicated by Ramaswamy H. Sarma.

The role of toll-like receptors (TLRs) in pan-cancer

BACKGROUND

Toll-like receptors (TLRs) are important components of the innate and adaptive immune systems, and abnormal TLR expression has been linked to a variety of cancers. However, there was a lack of clarity on the association of TLR stimulation with the carcinogenesis of cancer. The study's goal was to analyse the clinical importance of TLRs expression at the mRNA level in pan-cancer datasets, as well as the link between TLR expression and carcinogenesis, progression, and clinical prognosis.

METHODS

The expression profile of TLRs derived from UCSC pan-cancer data was analysed in multiple dimensions, including clinical analysis, immunological subtype analysis, tumour microenvironment (TME) analysis, tumour stem cell correlation analysis, and drug sensitivity analysis. Additionally, we analyse protein-protein interactions, functional enrichment, and chromatin accessibility, as well as TLR expression in single-cell sequencing data.

RESULTS

Our multi-omics analysis results imply that TLRs may operate as a biological marker for carcinogenesis and progression, a potential target for anti-tumour therapy, and a prognostic biomarker, laying the theoretical groundwork for future translational medicine research.

CONCLUSION

TLRs are involved in the formation of malignancies and can be explored in further detail as potential prognostic indicators. Key MessagesToll-like receptors (TLRs) are key factors in the process of the innate and adaptive immune response, and their aberrant expression of TLRs have been widely reported in various cancer. However, the association between TLRs stimulation and tumorigenesis of cancer has not been well clarified.In this study, in the pan-cancer data, integrated TLR family gene expression analysis, clinical correlation analysis, immune subtype correlation analysis, tumour microenvironment correlation analysis, tumour stem cell correlation analysis, and drug sensitivity correlation analysis were performed.TLRs play an important role in the development of tumours and can be studied in depth as potential prognostic markers.

The relationship between 896A/G (rs4986790) polymorphism of TLR4 and infectious diseases: A meta-analysis

Toll-like Receptors (TLRs), such as the TLR4, are genes encoding transmembrane receptors of the same name, which induce a pro- or anti-inflammatory response according to their expression as the host's first line of defense against pathogens, such as infectious ones. Single nucleotide polymorphisms (SNPs) are the most common type of mutation in the human genome and can generate functional modification in genes. The aim of this article is to review in which infectious diseases there is an association of susceptibility or protection by the TLR4 SNP rs4986790. A systematic review and meta-analysis of the literature was conducted in the Science Direct, PUBMED, MEDLINE, and SciELO databases between 2011 and 2021 based on the dominant genotypic model of this SNP for general and subgroup analysis of infectious agent type in random effect. Summary odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were calculated for genotypic comparison. I2 statistics were calculated to assess the presence of heterogeneity between studies and funnel plots were inspected for indication of publication bias. A total of 27 articles were included, all in English. Among the results achieved, the categories of diseases that were most associated with the SNP studied were in decreasing order of number of articles: infections by bacteria (29.63%); caused by viruses (22.23%); urinary tract infection-UTI (7.4%), while 11 studies (40.74%) demonstrated a nonsignificant association. In this meta-analysis, a total of 5599 cases and 5871 controls were finalized. The present meta-analysis suggests that there is no significant association between TLR4-rs4986790 SNP and infections (OR = 1,11; 95% CI: 0,75-1,66; p = 0,59), but in the virus subgroup it was associated with a higher risk (OR = 2,16; 95% CI: 1,09-4,30; p = 0,03). The subgroups of bacteria and parasites did not show statistical significance (OR = 0,86; 95% CI: 0,56-1,30; p = 0,47, and no estimate of effects, respectively). Therefore, it has been shown that a diversity of infectious diseases is related to this polymorphism, either by susceptibility or even severity to them, and the receptor generated is also crucial for the generation of cell signaling pathways and immune response against pathogens.

ROS-directed activation of Toll/NF-κB in the hematopoietic niche triggers benzene-induced emergency hematopoiesis

Hematopoietic stem cells/progenitor cells (HSC/HPCs) orchestrate the hematopoietic process, effectively regulated by the hematopoietic niche under normal and stressed conditions. The hematopoietic niche provides various soluble factors which influence the differentiation and self-renewal of HSC/HSPs. Unceasing differentiation/proliferation/high metabolic activity of HSC/HPCs makes them susceptible to damage by environmental toxicants like benzene. Oxidative stress, epigenetic modifications, and DNA damage in the HSC/HPCs are the key factors of benzene-induced hematopoietic injury. However, the role of the hematopoietic niche in benzene-induced hematopoietic injury/response is still void. Therefore, the current study aims to unravel the role of the hematopoietic niche in benzene-induced hematotoxicity using a genetically tractable model, Drosophila melanogaster. The lymph gland is a dedicated hematopoietic organ in Drosophila larvae. A group of 30-45 cells called the posterior signaling center (PSC) in the lymph gland acts as a niche that regulates Drosophila HSC/HPCs maintenance. Benzene exposure to Drosophila larvae (48 h) resulted in aberrant hemocyte production, especially hyper-differentiation of lamellocytes followed by premature lymph gland dispersal and reduced adult emergence upon developmental exposure. Subsequent genetic experiments revealed that benzene-induced lamellocyte production and premature lymph gland dispersal were PSC mediated. The genetic experiments further showed that benzene generates Dual oxidase (Duox)-dependent Reactive Oxygen Species (ROS) in the PSC, activating Toll/NF-κB signaling, which is essential for the aberrant hemocyte production, lymph gland dispersal, and larval survival. Together, the study establishes a functional perspective of the hematopoietic niche in a benzene-induced hematopoietic emergency in a genetic model, Drosophila, which might be relevant to higher organisms.

An updated systematic review of the association between the TLR4 polymorphism rs4986790 and cancers risk

BACKGROUND

Toll-like receptor 4 (TLR4) is a lipopolysaccharide receptor that may influence tumor progression through inflammatory response and immune response. This complex process mainly occurs within cells. The correlation between TLR4 and neoplasms has been of great interest, but discrepancies remain.

METHODS

We analyze the literature retrieved from five databases (Web of Science, PubMed, Embase, CNKI, and Wan Fang) to assess the intensity of association using odds ratio (ORs) and 95% confidence intervals (95% CI). Meta-regression and subgroup analysis were utilized to find sources of heterogeneity. Publication bias is estimated using contour-enhanced funnel plots, Begg's test, and Egger's test, and we implemented sensitivity analysis to clarify the reliability of the outcomes. We also conducted an evaluation of the sample size using trial sequential analysis (TSA) method.

RESULTS

We found a significant association between rs4986790 and tumors (dominant model: OR [95% CI] = 1.25 [1.11-1.42]; heterozygous model OR [95% CI] = 1.25 [1.11-1.41]; and additive model: OR [95% CI] = 1.25 [1.10-1.41]. Specifically, the rs4986790 minor allele G may increase the risk of gastric cancer (dominant model: OR [95% CI] = 1.62 [1.3-2.03]; heterozygous model: OR [95% CI] = 1.57 [1.24-1.97]; additive model: OR [95% CI] = 1.64 [1.31-2.05] and other tumors (dominant model: OR [95% CI] = 1.36 [1.17-1.57]; heterozygous model: OR [95% CI] = 1.43 [1.25-1.63]; additive model: OR [95% CI] = 1.35 [1.18-1.55]. Further subgroup analysis showed that this association are both present in Caucasian and Asian.

CONCLUSION

The outcomes of our systemic review proved that the TLR4 polymorphism rs4986790 is associated with cancer, especially with gastric cancer, and this strong correlation are evident in Caucasians and Asian.

Activation of TLR4 by viral glycoproteins: A double-edged sword?

Recognition of viral infection by pattern recognition receptors is paramount for a successful immune response to viral infection. However, an unbalanced proinflammatory response can be detrimental to the host. Recently, multiple studies have identified that the SARS-CoV-2 spike protein activates Toll-like receptor 4 (TLR4), resulting in the induction of proinflammatory cytokine expression. Activation of TLR4 by viral glycoproteins has also been observed in the context of other viral infection models, including respiratory syncytial virus (RSV), dengue virus (DENV) and Ebola virus (EBOV). However, the mechanisms involved in virus-TLR4 interactions have remained unclear. Here, we review viral glycoproteins that act as pathogen-associated molecular patterns to induce an immune response via TLR4. We explore the current understanding of the mechanisms underlying how viral glycoproteins are recognized by TLR4 and discuss the contribution of TLR4 activation to viral pathogenesis. We identify contentious findings and research gaps that highlight the importance of understanding viral glycoprotein-mediated TLR4 activation for potential therapeutic approaches.

Bioaerosol and microbial exposures from residential evaporative coolers and their potential health outcomes: A review

Evaporative cooling is an energy efficient form of air conditioning in dry climates that functions by pulling hot, dry outdoor air across a wet evaporative pad. While evaporative coolers can help save energy, they also have the potential to influence human health. Studies have shown residential evaporative coolers may pull outdoor air pollutants into the home or contribute to elevated levels of indoor bioaerosols that may be harmful to health. There is also evidence that evaporative coolers can enable a diverse microbial environment that may confer early-life immunological protection against the development of allergies and asthma or exacerbate these same hypersensitivities. This review summarizes the current knowledge of bioaerosol and microbiological studies associated with evaporative coolers, focusing on harmful and potentially helpful outcomes from their use. We evaluate the effects of evaporative coolers on indoor bacterial endotoxins, fungal β-(1 → 3)-D-glucans, dust mite antigens, residential microbial communities, and Legionella pneumophila. To our knowledge, this is the first review to summarize and evaluate studies on the influence that evaporative coolers have on the bioaerosol and microbiological profile of homes. This brings to light a gap in the literature on evaporative coolers, which is the lack of data on health effects associated with their use.

Single nucleotide polymorphisms in genes involved in immune responses and outcome of tegumentary leishmaniasis

Leishmaniases are neglected tropical diseases with a broad clinical spectrum. Tegumentary leishmaniasis (TL) is a disease caused by different Leishmania species, transmitted by phlebotomine sand flies and distributed worldwide. TL can present a cutaneous (CL) or mucocutaneous (MCL) clinical form depending on factors inherent to the parasite, the host and the vector. Polymorphisms in the immune response genes are host genetic factors that influence the pathogenesis or control of leishmaniasis. Single nucleotide polymorphisms (SNPs) in immune genes have been evaluated in several countries where leishmaniasis is endemic. In this review, we report studies on SNPs in several immune genes that might be associated with susceptibility or resistance to TL. We summarize studies from around the world and in Brazil, highlight the difficulties of these studies and future analyses needed to enhance our knowledge regarding host genetic factors in TL. Understanding the genetic characteristics of the host that facilitate resistance or susceptibility to leishmaniasis can contribute to the development of immunotherapy schedules for this disease. The current treatment methods are toxic, and no human vaccine is available.

Toll-Like Receptor 4 Signaling in the Trabecular Meshwork

Primary open-angle glaucoma is one of the leading causes of blindness worldwide. With limited therapeutics targeting the pathogenesis at the trabecular meshwork (TM), there is a great need for identifying potential new targets. Recent evidence has implicated Toll-like receptor 4 (TLR4) and it is signaling pathway in augmenting the effects of transforming growth factor beta-2 (TGFβ2) and downstream extracellular matrix production. In this review, we examine the role of TLR4 signaling in the trabecular meshwork and the interplay between endogenous activators of TLR4 (damage-associated molecular patterns (DAMPs)), extracellular matrix (ECM), and the effect on intraocular pressure.

Offense and Defense in Granulomatous Inflammation Disease

Granulomatous inflammation (GI) diseases are a group of chronic inflammation disorders characterized by focal collections of multinucleated giant cells, epithelioid cells and macrophages, with or without necrosis. GI diseases are closely related to microbes, especially virulent intracellular bacterial infections are important factors in the progression of these diseases. They employ a range of strategies to survive the stresses imposed upon them and persist in host cells, becoming the initiator of the fighting. Microbe-host communication is essential to maintain functions of a healthy host, so defense capacity of hosts is another influence factor, which is thought to combine to determine the result of the fighting. With the development of gene research technology, many human genetic loci were identified to be involved in GI diseases susceptibility, providing more insights into and knowledge about GI diseases. The current review aims to provide an update on the most recent progress in the identification and characterization of bacteria in GI diseases in a variety of organ systems and clinical conditions, and examine the invasion and escape mechanisms of pathogens that have been demonstrated in previous studies, we also review the existing data on the predictive factors of the host, mainly on genetic findings. These strategies may improve our understanding of the mechanisms underlying GI diseases, and open new avenues for the study of the associated conditions in the future.

Role of innate immune receptors TLR4 and TLR2 polymorphisms in systemic lupus erythematosus susceptibility

AIM

Through their recognition of various bacterial cell wall components, TLR2 and TLR4 participate in the innate response and modulate the activation of adaptive immunity. Therefore, the genetic background of these receptors might play a crucial role in autoimmune diseases such as systemic lupus erythematosus (SLE). In this study, we investigated the possible association between polymorphisms within TLR2 and TLR4 genes with SLE susceptibility.

MATERIAL AND METHODS

A total of 100 SLE patients and 200 unrelated healthy controls of the Tunisian population were enrolled in the study.TLR4rs4986790, TLR4rs4986791, and TLR2rs5743708 genotyping were performed using a polymerase chain reaction-restriction fragment length polymorphism method. The number of guanine-thymine (GT) repeat microsatellite in the intron 2 of TLR2 gene was analyzed by sequencing.

RESULTS

We reported a lack of allelic and genotypic association between SNPs of TLR4 and TLR2 genes and SLE pathogenesis. No correlation was found with any SLE features. However, SLE susceptibility was associated with the GT repeat microsatellite polymorphism in the human TLR2 gene. Further subclassification of alleles into three subclasses revealed a significant association between the long-sized repeats ((GT) >23) and SLE.

CONCLUSION

Though the results showed the absence of genetic association of TLR4 and TLR2 SNPs with the risk of developing SLE, we have identified a protective association between the microsatellite polymorphism in intron 2 of the TLR2 gene and SLE. Functionally, these (GT)n repeats may confer modifying effects or susceptibility to certain inflammatory conditions.

Mice Expressing Cosegregating Single Nucleotide Polymorphisms (D298G and N397I) in TLR4 Have Enhanced Responses to House Dust Mite Allergen

Asthma is a common and ubiquitous chronic respiratory disease that is associated with airway inflammation and hyperreactivity resulting in airway obstruction. It is now accepted that asthma is controlled by a combination of host genetics and environment in a rather complex fashion; however, the link between sensing of the environment and development and exacerbation of allergic lung inflammation is unclear. Human populations expressing cosegregating D299G and T399I polymorphisms in the TLR4 gene are associated with a decreased risk for asthma in adults along with hyporesponsiveness to inhaled LPS, the TLR4 ligand. However, these data do not account for other human genetic or environmental factors. Using a novel mouse strain that expresses homologous human TLR4 polymorphisms (TLR4-single nucleotide polymorphism [SNP]), we directly tested the effect of these TLR4 polymorphisms on in vivo responses to allergens using two models of induction. We report that intact TLR4 is required for allergic inflammation when using the OVA and LPS model of induction, as cellular and pathological benchmarks were diminished in both TLR4-SNP and TLR4-deficent mice. However, in the more clinically relevant model using house dust mite extract for induction, responses were enhanced in the TLR4-SNP mice, as evidenced by greater levels of eosinophilic inflammation, Th2 cytokine production, and house dust mite-specific IgG1 production compared with wild-type mice; however, mucus production and airway hyperreactivity were not affected. These results suggest that the TLR4 polymorphic variants (genes) interact differently with the allergic stimulation (environment).

Lung Hyaluronasome: Involvement of Low Molecular Weight Ha (Lmw-Ha) in Innate Immunity

Hyaluronic acid (HA) is a major component of the extracellular matrix. It is synthesized by hyaluronan synthases (HAS) into high-molecular-weight chains (HMW-HA) that exhibit anti-inflammatory and immunomodulatory functions. In damaged, infected, and/or inflamed tissues, HMW-HA are degraded by hyaluronidases (HYAL) or reactive oxygen species (ROS) to give rise to low-molecular-weight HAs (LMW-HAs) that are potent pro-inflammatory molecules. Therefore, the size of HA regulates the balance of anti- or pro-inflammatory functions. The activities of HA depend also on its interactions with hyaladherins. HA synthesis, degradation, and activities through HA/receptors interactions define the hyaluronasome. In this review, a short overview of the role of high and low-molecular-weight HA polymers in the lungs is provided. The involvement of LMW-HA in pulmonary innate immunity via the activation of neutrophils, macrophages, dendritic cells, and epithelial cells is described to highlight LMW-HA as a therapeutic target in inflammatory respiratory diseases. Finally, the possibilities to counter LMW-HA’s deleterious effects in the lungs are discussed.

Different expression patterns of inflammatory cytokines induced by lipopolysaccharides from Escherichia coli or Porphyromonas gingivalis in human dental pulp stem cells

Background

Lipopolysaccharide (LPS) is one of the leading causes of pulpitis. The differences in establishing an in vitro pulpitis model by using different lipopolysaccharides (LPSs) are unknown. This study aimed to determine the discrepancy in the ability to induce the expression of inflammatory cytokines and the underlying mechanism between Escherichia coli (E. coli) and Porphyromonas gingivalis (P. gingivalis) LPSs in human dental pulp stem cells (hDPSCs).

Material and methods

Quantitative real-time polymerase chain reaction (QRT-PCR) was used to evaluate the mRNA levels of inflammatory cytokines including IL-6, IL-8, COX-2, IL-1β, and TNF-α expressed by hDPSCs at each time point. ELISA was used to assess the interleukin-6 (IL-6) protein level. The role of toll-like receptors (TLR)2 and TLR4 in the inflammatory response in hDPSCs initiated by LPSs was assessed by QRT-PCR and flow cytometry.

Results

The E. coli LPS significantly enhanced the mRNA expression of inflammatory cytokines and the production of the IL-6 protein (p < 0.05) in hDPSCs. The peaks of all observed inflammation mediators’ expression in hDPSCs were reached 3–12 h after stimulation by 1 μg/mL E. coli LPS. E. coli LPS enhanced the TLR4 expression (p < 0.05) but not TLR2 in hDPSCs, whereas P. gingivalis LPS did not affect TLR2 or TLR4 expression in hDPSCs. The TLR4 inhibitor pretreatment significantly inhibited the gene expression of inflammatory cytokines upregulated by E. coli LPS (p < 0.05).

Conclusion

Under the condition of this study, E. coli LPS but not P. gingivalis LPS is effective in promoting the expression of inflammatory cytokines by hDPSCs. E. coli LPS increases the TLR4 expression in hDPSCs. P. gingivalis LPS has no effect on TLR2 or TLR4 expression in hDPSCs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-022-02161-x.

Assessing the Role of Lipopolysaccharide (LPS) Receptor (CD14) in Septic Cardiomyopathy: The Value of Immunohistochemical Diagnostics

Sepsis-induced myocardial dysfunction (SIMD) is one of the major predictors of morbidity and mortality of sepsis. A high percentage of patients with SIMD develop a status similar to cardiogenic shock. A high level of bacterial lipopolysaccharide (LPS) associated with an overexpression of CD14 acts as the trigger for the release of a broad spectrum of cytokines. Our study aimed to understand the correlation between septic cardiomyopathy and CD14 immunohistochemical expression. The study included 29 patients who died of septic shock. Increased values of membranous CD14 and soluble CD14 in the heart tissue were correlated with adverse patient evolution. A high cellular expression of CD14 was noted in the study group vs. the control group (p = 0.0013). Therefore, a close positive association between the amount of LPS related to sCD14 and the cellular expression of mCD14 is probable. By extrapolation, we suggest that a large amount of sCD14 detected in the cardiac tissue will activate the mCD14–TRL4–LBP–LPS complex, which in turn will induce an inadequate immune response, resulting in heart damage proportional to the amount of LPS. CD14 could represent a valuable marker for septic cardiomyopathy; thus, apoptosis of cardiomyocytes could be foreseen by its high value.

Evolution of toll-like receptor gene family in amphibians

The evolutionary position and lifestyle of amphibians highlights the important roles of the immune system in adaptive radiation and their adaptation to a complex pathogenic environment. Toll-like receptors (TLRs) are membrane-like sensors that recognize and bind conserved molecular motifs in pathogens to initiate downstream immune responses. To understand the evolutionary patterns of TLRs in amphibians, we analyzed TLR genes from the genomes and transcriptomes of 102 amphibian species. Phylogenetic results showed that 578 intact amphibian TLR sequences belonged to 16 TLR genes and were divided into seven subfamilies. The TLR4 subfamily was only identified in the Anura. Purification selection plays a leading role in amphibian TLR evolution and mean ω (dN/dS) values ranged from 0.252 for TLR7 to 0.381 for TLR19. Furthermore, the ω values of different domains were significantly different. We found positive selection patterns for 141 of 12,690 codons (1.1%) in all amphibian TLRs, most of which were located in leucine-rich repeats (LRRs). We also observed low to moderate levels of single-nucleotide polymorphisms (SNPs) in Pelophylax nigromaculatus and Bombina orientalis. This study provided critical primers, meaningful information regarding TLR gene family evolution in amphibians, and insights into the complex evolutionary patterns and implications of TLR polymorphisms.

SARS-CoV-2 aerosol transmission and detection

Aerosol transmission has been officially recognized by the world health authority resulting from its overwhelming experimental and epidemiological evidences. Despite substantial progress, few additional actions were taken to prevent aerosol transmission, and many key scientific questions still await urgent investigations. The grand challenge, the effective control of aerosol transmission of COVID-19, remains unsolved. A better understanding of the viral shedding into the air has been developed, but its temporal pattern is largely unknown. Sampling tools, as one of the critical elements for studying SARS-CoV-2 aerosol, are not readily available around the world. Many of them are less capable of preserving the viability of SARS-CoV-2, thus offering no clues about viral aerosol infectivity. As evidenced, the viability of SARS-CoV-2 is also directly impacted by temperature, humidity, sunlight, and air pollutants. For SARS-CoV-2 aerosol detection, liquid samplers, together with real-time polymerase chain reaction (RT-PCR), are currently used in certain enclosed or semi-enclosed environments. Sensitive and rapid COVID-19 screening technologies are in great need. Among others, the breath-borne-based method emerges with global attention due to its advantages in sample collection and early disease detection. To collectively confront these challenges, scientists from different fields around the world need to fight together for the welfare of mankind. This review summarized the current understanding of the aerosol transmission of SARS-CoV-2 and identified the key knowledge gaps with a to-do list. This review also serves as a call for efforts to develop technologies to better protect the people in a forthcoming reopening world.

eIF3k inhibits NF-κB signaling by targeting MyD88 for ATG5-mediated autophagic degradation in teleost fish

Optimal activation of NF-κB signaling is crucial for the initiation of inflammatory responses and eliminating invading bacteria. Bacteria have likewise evolved the ability to evade immunity; however, mechanisms by which bacteria dysregulate host NF-κB signaling are unclear. In this study, we identify eukaryotic translation initiation factor eIF3k, a nonessential member of the eIF3 translation initiation complex, as a suppressor of the NF-κB pathway. Mechanistically, we show that eIF3k expression induced by Vibrio harveyi enhances E3 ligase Nrdp1-mediated K27-linked ubiquitination of MyD88, an upstream regulator of NF-κB pathway activation. Furthermore, we show that eIF3k acts as a bridge linking ubiquitin-tagged MyD88 and ATG5, an important mediator of autophagy. We demonstrate that the MyD88-eIF3k-ATG5 complex is transported to the autophagosome for degradation, and that innate immune signaling is subsequently terminated and does not attack invading V. harveyi. Therefore, our study identifies eIF3k as a specific inhibitor of the MyD88-dependent NF-κB pathway and suggests that eIF3k may act as a selective autophagic receptor that synergizes with ATG5 to promote the autophagic degradation of MyD88, which helps V. harveyi to evade innate immunity. We conclude that V. harveyi can manipulate a host's autophagy process to evade immunity in fish and also provide a new perspective on mammalian resistance to bacterial invasion.

Toll-Like Receptor 4 in Pain: Bridging Molecules-to-Cells-to-Systems

Pain impacts the lives of billions of people around the world - both directly and indirectly. It is complex and transcends beyond an unpleasant sensory experience to encompass emotional experiences. To date, there are no successful treatments for sufferers of chronic pain. Although opioids do not provide any benefit to chronic pain sufferers, they are still prescribed, often resulting in more complications such as hyperalgesia and dependence. In order to develop effective and safe medications to manage, and perhaps even treat pain, it is important to evaluate novel contributors to pain pathologies. As such, in this chapter we review the role of Toll-like receptor 4, a receptor of the innate immune system, that continues to gain substantial attention in the field of pain research. Positioned in the nexus of the neuro and immune systems, TLR4 may provide one of the missing pieces in understanding the complexities of pain. Here we consider how TLR4 enables a mechanistical understanding of pain as a multidimensional biopsychosocial state from molecules to cells to systems and back again.