Toll-like receptors and integrins crosstalk

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

Dental Biofilm and Saliva Microbiome and Its Interplay with Pediatric Allergies

Little is known about the interplay and contribution of oral microorganisms to allergic diseases, especially in children. The aim of the clinical study was to associate saliva and dental biofilm microbiome with allergic disease, in particular with allergic asthma. In a single-center study, allergic/asthmatic children (n = 15; AA-Chd; age 10.7 ± 2.9), atopic/allergic children (n = 16; AT/AL-Chd; 11.3 ± 2.9), and healthy controls (n = 15; CON-Chd; age 9.9 ± 2.2) were recruited. After removing adhering biofilms from teeth and collecting saliva, microbiome was analyzed by using a 16s-rRNA gene-based next-generation sequencing in these two mediums. Microbiome structure differed significantly between saliva and dental biofilms (β-diversity). Within the groups, the dental biofilm microbiome of AA-Chd and AT/AL-Chd showed a similar microbial fingerprint characterized by only a small number of taxa that were enriched or depleted (4) compared to the CON-Chd, while both diseased groups showed a stronger microbial shift compared to CON-Chd, revealing 14 taxa in AA-Chd and 15 taxa in AT/AL-Chd that were different. This could be the first note to the contribution of dental biofilm and its metabolic activity to allergic health or disease

Timing of Blood Sample Processing Affects the Transcriptomic and Epigenomic Profiles in CD4+ T-cells of Atopic Subjects

Optimal pre-analytical conditions for blood sample processing and isolation of selected cell populations for subsequent transcriptomic and epigenomic studies are required to obtain robust and reproducible results. This pilot study was conducted to investigate the potential effects of timing of CD4+ T-cell processing from peripheral blood of atopic and non-atopic adults on their transcriptomic and epigenetic profiles. Two heparinized blood samples were drawn from each of three atopic and three healthy individuals. For each individual, CD4+ T-cells were isolated from the first blood sample within 2 h (immediate) or from the second blood sample after 24 h storage (delayed). RNA sequencing (RNA-Seq) and histone H3K27 acetylation chromatin immunoprecipitation sequencing (ChIP-Seq) analyses were performed. A multiplicity of genes was shown to be differentially expressed in immediately processed CD4+ T-cells from atopic versus healthy subjects. These differences disappeared when comparing delayed processed cells due to a drastic change in expression levels of atopy-related genes in delayed processed CD4+ T-cells from atopic donors. This finding was further validated on the epigenomic level by examining H3K27 acetylation profiles. In contrast, transcriptomic and epigenomic profiles of blood CD4+ T-cells of healthy donors remained rather unaffected. Taken together, for successful transcriptomics and epigenomics studies, detailed standard operation procedures developed on the basis of samples from both healthy and disease conditions are implicitly recommended

Identification of underlying molecular mechanisms of obesity-associated asthma

In the evolution of personalized medicine and stratified therapies, comprehensive understanding of the molecular mechanisms underlying different disease phenotypes, such as asthma phenotypes including obesity-associated asthma, are urgently needed. Biological pathways and functions of differentially expressed genes and miRNAs can play an essential role in the development and severity of obesity-related asthma. To fulfill this purpose, a preliminary work was initiated to establish optimal experimental conditions by investigating the effects related to different timings of CD4+ T cells processing from peripheral blood. Thus, 2 peripheral blood samples were drawn from each of 3 atopic patients and 3 healthy donors (12 samples), CD4+ T cells isolation was conducted from the first blood sample within two hours (Immediate) and from the second blood sample after 24 hours (Delayed), transcriptomic profiles of CD4+ T cells were examined using RNA-Seq analysis and readouts were verified on the epigenetic level through the H3K27ac ChIP-Seq analysis. After a successful establishment of ideal experimental conditions, peripheral blood was drawn from 10 obese, non-atopic asthmatic adults with a high body mass index (BMI; 36.67 ± 6.90), 10 non-obese, non- atopic asthmatic adults with normal BMI (23.88 ± 2.73), and 10 healthy controls with normal BMI (23.62 ± 3.74). All asthmatic patients were considered to have a low type- 2 asthma phenotype according to blood eosinophils counts, FeNO and IgE levels criteria. Peripheral blood CD4+ T cells were isolated, mRNA sequencing was conducted. Moreover, plasma was also taken from the same blood samples of the same previous individuals, EVs were isolated, EVs RNA was extracted and small/microRNA-Seq was performed. The transcriptomic profiles of delayed processed CD4+ T cells showed only 3 differentially expressed genes at FDR < 0.1 when comparing atopic with healthy individuals. CD4+ T cells of healthy donors were not harshly affected by the delayed ex vivo blood incubation, while a drastic change has been shown in CD4+ T cells of atopic patients following the delayed blood processing accompanying by downregulation atopy-related biological pathways such as IL-2 and IL-17 signaling pathways. Concordant results were observed on the epigenetic level through H3K27ac profiles. IFN signaling pathways dominated the CD4+ T cells responses solely in low type-2 obese asthmatics represented by upregulation of different ISGs such as IFITM3, IFIT3, OAS2, OAS3, EIF2AK2, MX1, USP18, GBP3 genes, which correlated positively with lung function parameters including FEV1, FVC, VC max, TIFF, IC and PEF and negatively with the airway inflammation marker; FeNO. Viral infection pathways were also enriched for low type-2 obese asthmatics augmented by upregulation of different toll-like receptor genes such as TLR1, TLR-2, TLR-3, TLR-4, TLR-6, and TLR-8. Furthermore, obesity gene markers like IL15 and SOCS3 were also up-regulated in CD4+ T cells from obese asthmatics compared to both non-obese asthmatics and healthy controls. On the other hand, gap junction and GPCR ligand binding pathways were enriched in both low type-2 asthma groups. EVs miRNA clusters such as miR- 2329 and miR-106b seemed to be assigned to IFN signaling and viral infection pathways, respectively, in low type-2 obese asthmatics. In addition, single Plasma EV downregulated miRNAs including miR-665, miR-4419b, miR-4769-3p, miR-6893-5p, miR-4743-3p, miR-6721-5p, miR-1207-5p, miR-6132, miR-4700-3p, miR-4731-5p, miR-5089-5p, miR-502-5p, miR-6088, miR-148a-5p and miR-373-3p seemed to target most of the enriched ISGs of IFN signaling pathway in CD4+ T cells. In conclusion, the dominance of the IFN signaling pathways and their association with viral infection pathways in CD4+ T cells response could underpin the underlying molecular mechanism of low type-2 obesity-associated asthma. The IFN signaling pathway enriched ISGs, their associated miRNAs and other miRNA clusters might be a target for biological and stratified therapies for this unique asthma phenotype

Effects of obesity on asthma: immunometabolic links.

Asthma is a widespread chronic inflammatory disease, which has a highly heterogeneous etiopathogenesis, with predominance of either T‑helper cell type 2 (Th2; type 2) or non-Th2 (non-type 2) mechanisms. Together with cardiovascular or autoimmune diseases, obesity, and others, asthma belongs to so called noncommunicable diseases, a group of disorders with immunometabolic links as underlying mechanisms. So far, obesity and asthma have been considered mostly independently, but there are clear signs of relevant interactions. First, obese patients are at increased risk of asthma or asthma‑like symptoms. Second, asthma accompanied by obesity is more severe and more difficult to treat. A specific phenotype called obesity‑associated asthma has been also described, which is late‑onset, rather severe, non-type 2‑driven disease, present mostly in women. In addition, obesity can coincide with asthma also in children, and, although obesity generally skews the Th1/Th2 balance towards Th1, it can also accompany type 2‑driven asthma. However, those combinations represent less precisely defined disease entities. Despite a substantial increase in our knowledge on the mechanisms mediating the effects of obesity on the development of asthma in several recent years, still much needs to be done, especially on the molecular level

Differential Regulation of Interferon Signaling Pathways in CD4+ T Cells of the Low Type-2 Obesity-Associated Asthma Phenotype

In the era of personalized medicine, insights into the molecular mechanisms that differentially contribute to disease phenotypes, such as asthma phenotypes including obesity-associated asthma, are urgently needed. Peripheral blood was drawn from 10 obese, non-atopic asthmatic adults with a high body mass index (BMI; 36.67 ± 6.90); 10 non-obese, non-atopic asthmatic adults with normal BMI (23.88 ± 2.73); and 10 healthy controls with normal BMI (23.62 ± 3.74). All asthmatic patients were considered to represent a low type-2 asthma phenotype according to selective clinical parameters. RNA sequencing (RNA-Seq) was conducted on peripheral blood CD4+ T cells. Thousands of differentially expressed genes were identified in both asthma groups compared with heathy controls. The expression of interferon (IFN)-stimulated genes associated with IFN-related signaling pathways was specifically affected in obese asthmatics, while the gap junction and G protein-coupled receptor (GPCR) ligand binding pathways were enriched in both asthma groups. Furthermore, obesity gene markers were also upregulated in CD4+ T cells from obese asthmatics compared with the two other groups. Additionally, the enriched genes of the three abovementioned pathways showed a unique correlation pattern with various laboratory and clinical parameters. The specific activation of IFN-related signaling and viral infection pathways might provide a novel view of the molecular mechanisms associated with the development of the low type-2 obesity-associated asthma phenotype, which is a step ahead in the development of new stratified therapeutic approaches

Identification of extracellular vesicle microRNA signatures specifically linked to inflammatory and metabolic mechanisms in obesity-associated low type-2 asthma

International audienceRationale and Objective Plasma extracellular vesicles (EVs) represent a vital source of molecular information about health and disease states. Due to their heterogenous cellular sources, EVs and their cargo may predict specific pathomechanisms behind disease phenotypes. Here we aimed to utilize EV microRNA (miRNA) signatures to gain new insights into underlying molecular mechanisms of obesity-associated low type-2 asthma. Methods Obese low type-2 asthma (OA) and non-obese low type-2 asthma (NOA) patients were selected from an asthma cohort conjointly with healthy controls. Plasma EVs were isolated and characterised by nanoparticle tracking analysis. EV-associated small RNAs were extracted, sequenced and bioinformatically analysed. Results Based on EV miRNA expression profiles, a clear distinction between the three study groups could be established using a principal component analysis. Integrative pathway analysis of potential target genes of the differentially expressed miRNAs revealed inflammatory cytokines (e.g., interleukin-6, transforming growth factor-beta, interferons) and metabolic factors (e.g., insulin, leptin) signalling pathways to be specifically associated with OA. The miR-17–92 and miR-106a–363 clusters were significantly enriched only in OA. These miRNA clusters exhibited discrete bivariate correlations with several key laboratory (e.g., C-reactive protein) and lung function parameters. Plasma EV miRNA signatures mirrored blood-derived CD4+ T-cell transcriptome data, but achieved an even higher sensitivity in identifying specifically affected biological pathways. Conclusion The identified plasma EV miRNA signatures and particularly the miR-17–92 and -106a–363 clusters were capable to disentangle specific mechanisms of the obesity-associated low type-2 asthma phenotype, which may serve as basis for stratified treatment development

Histone modifications and their role in epigenetics of atopy and allergic diseases

This review covers basic aspects of histone modification and the role of posttranslational histone modifications in the development of allergic diseases, including the immune mechanisms underlying this development. Together with DNA methylation, histone modifications (including histone acetylation, methylation, phosphorylation, ubiquitination, etc.) represent the classical epigenetic mechanisms. However, much less attention has been given to histone modifications than to DNA methylation in the context of allergy. A systematic review of the literature was undertaken to provide an unbiased and comprehensive update on the involvement of histone modifications in allergy and the mechanisms underlying this development. In addition to covering the growing interest in the contribution of histone modifications in regulating the development of allergic diseases, this review summarizes some of the evidence supporting this contribution. There are at least two levels at which the role of histone modifications is manifested. One is the regulation of cells that contribute to the allergic inflammation (T cells and macrophages) and those that participate in airway remodeling [(myo-) fibroblasts]. The other is the direct association between histone modifications and allergic phenotypes. Inhibitors of histone-modifying enzymes may potentially be used as anti-allergic drugs. Furthermore, epigenetic patterns may provide novel tools in the diagnosis of allergic disorders

In vitro induction of human embryonal carcinoma differentiation by a crude extract of Rhazya stricta

Abstract Background Rhazya stricta Decne. is a medicinal plant that is widespread in Saudi Arabia and desert areas of the Arabian Peninsula. Its extract contains alkaloids, tannins, and flavonoids that are involved in different biological activities. The study aim was to evaluate the effects of Rhazya stricta plant extracts on the proliferation and differentiation of NTERA-2 (NT2) pluripotent embryonal carcinoma cells. Methods Soxhlet extraction was carried out using different solvents to extract stems, leaves and fruit parts of this plant. Cytotoxicity was evaluated by an MTS cell viability assay. The ability of the plant extract to induce cell differentiation was examined phenotypically using an inverted light microscope. The expression of pluripotency markers was investigated by reverse transcriptase polymerase chain reaction (RT-PCR) and immunocytochemistry. Phytochemical screening of chloroform stem extracts was carried out and a chromatographic fingerprint was generated using gas chromatography – mass spectrometry (GC-MS). Results Chloroform stem extract induced differentiation of NT2 cells at 5 μg/ml, and the differentiated cells exhibited neurite formation. Following induction of differentiation, there was significant down-regulation of the pluripotency marker genes Oct4 and Sox2. In addition, the surface antigen pluripotency marker, TRA-1-60, was strongly down-regulated. Phytochemical analysis of the extract showed the presence of alkaloids and saponins. The chromatogram revealed the presence of fifteen compounds with different retention times. Conclusion Our results demonstrate for the first time that chloroform stem extract of R. stricta can induce neuronal differentiation of stem cells at an early stage and may contain potential therapeutic agent that can be used in neurodegenerative diseases

Raw Cow's Milk Reduces Allergic Symptoms in a Murine Model for Food Allergy-A Potential Role For Epigenetic Modifications

Epidemiological studies identified raw cow's milk consumption as an important environmental exposure that prevents allergic diseases. In the present study, we investigated whether raw cow's milk has the capacity to induce tolerance to an unrelated, non-milk, food allergen. Histone acetylation of T cell genes was investigated to assess potential epigenetic regulation. Female C3H/HeOuJ mice were sensitized and challenged to ovalbumin. Prior to sensitization, the mice were treated with raw milk, processed milk, or phosphate-buffered saline for eight days. Allergic symptoms were assessed after challenge and histone modifications in T cell-related genes of splenocyte-derived CD4+ T cells and the mesenteric lymph nodes were analyzed after milk exposure and after challenge. Unlike processed milk, raw milk decreased allergic symptoms. After raw milk exposure, histone acetylation of Th1-, Th2-, and regulatory T cell-related genes of splenocyte-derived CD4+ T cells was higher than after processed milk exposure. After allergy induction, this general immune stimulation was resolved and histone acetylation of Th2 genes was lower when compared to processed milk. Raw milk reduces allergic symptoms to an unrelated, non-milk, food allergen in a murine model for food allergy. The activation of T cell-related genes could be responsible for the observed tolerance induction, which suggested that epigenetic modifications contribute to the allergy-protective effect of raw milk