NLRP12-PANoptosome activates PANoptosis and pathology in response to heme and PAMPs.

Cytosolic innate immune sensors are critical for host defense and form complexes, such as inflammasomes and PANoptosomes, that induce inflammatory cell death. The sensor NLRP12 is associated with infectious and inflammatory diseases, but its activating triggers and roles in cell death and inflammation remain unclear. Here, we discovered that NLRP12 drives inflammasome and PANoptosome activation, cell death, and inflammation in response to heme plus PAMPs or TNF. TLR2/4-mediated signaling through IRF1 induced Nlrp12 expression, which led to inflammasome formation to induce maturation of IL-1ß and IL-18. The inflammasome also served as an integral component of a larger NLRP12-PANoptosome that drove inflammatory cell death through caspase-8/RIPK3. Deletion of Nlrp12 protected mice from acute kidney injury and lethality in a hemolytic model. Overall, we identified NLRP12 as an essential cytosolic sensor for heme plus PAMPs-mediated PANoptosis, inflammation, and pathology, suggesting that NLRP12 and molecules in this pathway are potential drug targets for hemolytic and inflammatory diseases.

DDX5 inhibits inflammation by modulating m6A levels of TLR2/4 transcripts during bacterial infection.

DExD/H-box helicases are crucial regulators of RNA metabolism and antiviral innate immune responses; however, their role in bacteria-induced inflammation remains unclear. Here, we report that DDX5 interacts with METTL3 and METTL14 to form an m6A writing complex, which adds N6-methyladenosine to transcripts of toll-like receptor (TLR) 2 and TLR4, promoting their decay via YTHDF2-mediated RNA degradation, resulting in reduced expression of TLR2/4. Upon bacterial infection, DDX5 is recruited to Hrd1 at the endoplasmic reticulum in an MyD88-dependent manner and is degraded by the ubiquitin-proteasome pathway. This process disrupts the DDX5 m6A writing complex and halts m6A modification as well as degradation of TLR2/4 mRNAs, thereby promoting the expression of TLR2 and TLR4 and downstream NF-κB activation. The role of DDX5 in regulating inflammation is also validated in vivo, as DDX5- and METTL3-KO mice exhibit enhanced expression of inflammatory cytokines. Our findings show that DDX5 acts as a molecular switch to regulate inflammation during bacterial infection and shed light on mechanisms of quiescent inflammation during homeostasis.

Immune response to cold exposure: Role of γδ T cells and TLR2-mediated inflammation.

The mammalian body possesses remarkable adaptability to cold exposure, involving intricate adjustments in cellular metabolism, ultimately leading to thermogenesis. However, cold-induced stress can impact immune response, primarily through noradrenaline-mediated pathways. In our study, we utilized a rat model subjected to short-term or long-term mild cold exposure to investigate systemic immune response during the cold acclimation. To provide human relevance, we included a group of regular cold swimmers in our study. Our research revealed complex relationship between cold exposure, neural signaling, immune response, and thermogenic regulation. One-day cold exposure triggered stress response, including cytokine production in white adipose tissue, subsequently activating brown adipose tissue, and inducing thermogenesis. We further studied systemic immune response, including the proportion of leukocytes and cytokines production. Interestingly, γδ T cells emerged as possible regulators in the broader systemic response, suggesting their possible contribution in the dynamic process of cold adaptation. We employed RNA-seq to gain further insights into the mechanisms by which γδ T cells participate in the response to cold. Additionally, we challenged rats exposed to cold with the Toll-like receptor 2 agonist, showing significant modulation of immune response. These findings significantly contribute to understanding of the physiological acclimation that occur in response to cold exposure.

Nonspecific lipid-transfer proteins trigger TLR2 and NOD2 signaling and undergo ligand-dependent endocytosis in epithelial cells.

BACKGROUND: Allergens can cross the epithelial barrier to enter the body but how this cellular passage affects protein structures and the downstream interactions with the immune system are still open questions. OBJECTIVE: We sought to show the molecular details and the effects of 3 nonspecific lipid transfer proteins (nsLTPs; Mal d 3 [allergenic nsLTP1 from apple], Cor a 8 [allergenic nsLTP1 from hazelnut], and Pru p 3 [allergenic nsLTP1 from peach]) on epithelial cell uptake and transport. METHODS: We used fluorescent imaging, flow cytometry, and proteomic and lipidomic screenings to identify the mechanism involved in nsLTP cellular uptake and signaling on selected epithelial and transgenic cell lines. RESULTS: nsLTPs are transported across the epithelium without affecting cell membrane stability or viability, and allergen uptake was largely impaired by inhibition of clathrin-mediated endocytosis. Analysis of the lipidome associated with nsLTPs showed a wide variety of lipid ligands predicted to bind inside the allergen hydrophobic cavity. Importantly, the internalization of nsLTPs was contingent on these ligands in the protein complex. nsLTPs were found to initiate cellular signaling via Toll-like receptor 2 but not the cluster of differentiation 1 protein receptor, despite neither being essential for nsLTP endocytosis. We also provide evidence that the 3 allergens induced intracellular stress signaling through activation of the NOD2 pathway. CONCLUSIONS: Our work consolidates the current model on nsLTP-epithelial cell interplay and adds molecular details about cell transport and signaling. In addition, we have developed a versatile toolbox to extend these investigations to other allergens and cell types.

Mono-palmitoyl-N-alkylurea ligands as specific activators of human Toll-like receptor 2/6 heterodimer.

Ligands for Toll-like-receptor 2 (TLR2) have demonstrated significant potential as immune-stimulating components in synthetic vaccines. Activation of TLR2 relies on the formation of dimeric complexes with either TLR1 or TLR6 and the nature of these dimers can impact therapeutic outcomes. The lipopeptide-based TLR2 ligands Pam3CysSK4 and Pam2CysSK4 have been extensively studied, and their recognition by different TLR-receptor heterodimers, TLR2/TLR1 and TLR2/TLR6, respectively, has been established. However, the high lipophilicity of these ligands, containing multiple palmitoyl residues, can result in solubility issues when used as vaccine adjuvants. To address this, we previously synthesized a less lipophilic ligand containing a single palmitoyl chain called mini-UPam, which effectively stimulates human moDC maturation. We here probe the receptor-dimer specificity of several mini-Upam derivatives and reveal that these mini-UPam are hTLR2/TLR6 selective ligands and that the introduction of longer urea alkyl chains does not shift the binding specificity to hTLR2/TLR1 heterodimers, in contrast to their Pam2CysSK4 and Pam3CysSK4 counterparts, pointing to a different binding mode of the UPam ligands.

Neutralization of TLR2 in combination with either TNF-α or IL-1ß antibody reduces the severity of septic arthritis through STAT3/mTOR signalling in lymphocytes.

Staphylococcus aureus induced Septic arthritis is considered a medical concern. S.aureus binds TLR2 to induce an array of inflammatory responses. Generation of pro-inflammatory cytokines induces T cell responses and control Th17/Treg cell balance. Regulation of T cell-mediated immunity in response to inflammation is significantly influenced by mTOR. Presence of elevated TNF-α, IL-1ß decreases Treg cell activity through STAT3/mTOR, promoting proliferation of T cells towards Th17 cells. Therefore, we postulated, neutralizing TLR2 with either TNF-α or IL-1ß in combination could be useful in modifying Th17/Treg cell ratio in order to treat septic arthritis by suppressing expression of mTOR/STAT3. To date, no studies have reported effects of neutralization of TLR2 along with either TNF-α or IL-1ß on amelioration of arthritis correlating with mTOR/STAT3 expression. Contribution of T lymphocytes collected from blood, spleen, synovial tissues, their derived cytokines IFN-γ, IL-6, IL-17, TGF-ß, IL-10 were noted. Expression of TLR2, TNFR1, TNFR2, NF-κB along with mTOR/STAT3 also recorded. Neutralization of TLR2 along with TNF-α and IL-1ß were able to shift Th17 cells into immunosuppressive Treg cells. Furthermore,elevated expression of IL-10, TNFR2 and demoted expression of mTOR/ STAT3 along with NF-κB in lymphocytes confirms its role in resolution of arthritis. It was also effective in reducing oxidative stress via increasing expression of the antioxidant enzymes. As a result, it can be inferred that Treg-derived IL-10, which may mitigate inflammatory effects of septic arthritis by influencing the mTOR/STAT3 interaction in lymphocytes, may be selected as a different therapeutic strategy for reducing the impact of septic arthritis.

Dynamic m6 A profiles reveal the role of YTHDC2-TLR2 signaling axis in Talaromyces marneffei infection.

Talaromyces marneffei (TM) immune evasion is an important factor leading to the high mortality rate of Penicilliosis marneffei. N6 -methyladenosine (m6 A) plays important roles in host immune response to various pathogen infections, yet its role in TM and HIV/TM coinfection remains largely unexplored. Here we reported genome-wide transcriptional m6 A profiles of TM mono-infection and HIV/TM coinfection. Our finding revealed dynamic alterations in global m6 A levels and upregulation of the m6 A reader YTH N6 -methyladenosine RNA binding protein C2 (YTHDC2) in TM-infected macrophages. Knockdown of YTHDC2 in TM-infected cells showed an elevated expression of TLR2 through m6 A-dependence, along with upregulation of TNF-α and IL1-ß. Overall, we characterized the m6 A profiles of the host and fungus before and after TM infection, and demonstrated that YTHDC2 mediates the key m6 A site of TLR2 to exert its function. These findings provide new insights into the underlying mechanisms and novel therapeutic approaches for TM diseases.

Unveiling the role of sTLR2: A novel biomarker for predicting septic-associated AKI.

BACKGROUND: Acute kidney injury (AKI) is common in septic patients and strongly associated with adverse outcomes. The pathophysiology of AKI in septic patients remains elusive, and detection of patients at risk of AKI or at risk of progression to severe and persistent AKI is critical for timely and adequate support measures, including mitigating further renal damage. Therefore, identification of biomarkers associated with septic-associated AKI that contribute to improve septic AKI is an area of intensive research. METHODS: A total of 116 consecutive patients with sepsis were categorized into two groups (AKI and non-AKI) based on the occurrence of AKI within 24 h of admission to the intensive care unit (ICU). Serum levels of soluble TLR2 (sTLR2), as well as biomarkers such as interleukin(IL)-6, IL-22, IL-10, creatinine, urea, procalcitonin, hypersensitive C-reactive protein (hs-CRP), and D-Dimer (D2), were measured within 24 h after ICU admission. Demographic and clinical characteristics including sequential organ failure assessment (SOFA) scores and acute physiology and chronic health evaluation II (APACHE II) scores were recorded. Logistic regression analysis was conducted to identify potential predictive biomarkers. Receiver operating characteristic (ROC) curve analysis was employed to determine the optimal model for predicting septic-associated AKI. RESULTS: Patients in the AKI group exhibited significantly higher serum concentrations of IL-6, IL-10, sTLR2, creatinine, urea, hs-CRP, procalcitonin, D2 and lower serum albumin concentrations as well as higher APACHE II scores compared to those in the non-AKI group. Logistic regression analysis revealed that APACHE II scores, log10-transformed sTLR2 concentration, creatinine and D2 concentration were valuable predictors of AKI among septic patients. ROC curves demonstrated that log10-transformed sTLR2 concentration exhibited comparable predictive value to creatinine in determining the incidence of sepsis-associated AKI. The model with variables of APACHE II score, Log10-transformed serum TLR2 concentration, creatinine and D2 concentration yielded the greatest area under the curve of 0.863. CONCLUSION: Elevated levels of sTLR2 in early-stage of septic patients may serve as a promising novel biomarker for predicting sepsis-associated AKI.

Immune response to colonization of Candida albicans in mice treated with Cefoperazone.

Candida species are a normal human flora in humans' digestive and reproductive systems, oral cavity, skin, and mucosal surfaces. This study aimed to detect the immunological role of Candida infection by using some immunological markers. The results of levels in serum showed high concentrations of IgA (56.20 ± 12 pg/ml,29.55 ± 4.5 pg/ml respectively) and IgG (12.05 ± 3.218 pg/ml, 3.836 ± 1.23 pg/ml respectively) in mice infected with C. albicans and mice treated with Cefoperazone and infected with Candida with significant differences (P value < 0.05). The results showed high serum levels of IL-17(191.5 ± 42.81 pg/ml) and TLR2(7.651 ± 1.5 pg/ml) in group mice infected with C. albicans compared with negative control and group mice treated with Cefoperazone. Also, high levels of IL-17 (91.33 ± 4.816 pg/ml) and TLR2 (2.630 ± 0.5 pg/ml) in group mice treated with Cefoperazone and infected with Candida compared with negative control and group mice treated with Cefoperazone (P value < 0.05). The results of antibodies and immunological markers in the intestine showed high levels of IgA and IgG in mice infected with C.albicans (55.7 ± 4.9 pg/ml, 18.19 ± 0.63 pg/ml respectively).Also,IgA and IgG in mice treated with Cefoperazone and infected with Candida were high level (43.04 ± 2.1 pg/ml, 2.927 ± 0.2 pg/ml respectively) in mice infected with C. albicans with significant differences (P value < 0.05). The results levels of IL-17 and TLR2 were increased in mice infected with C. albicans (191.5 ± 42.81 pg/ml, 7.651 ± 1.5 pg/ml respectively) and mice treated with Cefoperazone and infected with Candida (91.33 ± 4.816 pg/ml,2.630 ± 0.5 pg/ml respectively) with significant differences (P < 0.05). In conclusion, this study demonstrated that cefoperazone treatment and infection by Candida albicans changed the microbiome components in the gut and finally can change host immune responses. It was observed that elevated levels of the antibodies production (IgA and IgG) and immunological markers (IL-17, and TLR2) in serum and the gut.

Endogenous blocking of TLR2 along with TNF-α and IL-1ß ameliorates the severity of the S. aureus arthritis via modulating STAT3/SOCS3 expressions in tissue resident macrophages.

In vivo studies identifying a role of TLR2 in septic arthritis models are lacking. TNF-α played as the most important proinflammatory cytokine, and connected directly to the pathogenesis of bacterial arthritis. IL-1ß is another central mediator cytokine in arthritis. It is therefore reasonable to question the role of neutralization of endogenous TNF-α and IL-1ß along with TLR2 and associated downstream signaling as crucial mediators in the S. aureus -induced inflammatory arthritis. In reaction to an injury or a pathogen encounter, innate immune cells serve as the initial line of defense. TLR2 mediated entry of S. aureus into macrophage cells initiates an array of inflammatory cascades. After macrophage cell gets activated at the site inflammation, they generate elevated number of cytokines which includes TNF-α, IL-1ß. This cytokines signals through STAT1/STAT3 mediated pathways. Thus, aim of this study was to discover how This bone damage could be altered by altering the STAT/STAT3/SOCS3 ratio by blocking TLR2, a particular S. aureus binding site, in conjunction with the use of IL-1 and TNF- antibodies for neutralizing endogenous IL-1ß and TNF-α. Additionally, the role of local macrophages in therapy of arthritis was investigated in synovial and Splenic tissue. To comprehend the inflammatory milieu within the system, ROS and other antioxidant enzymes, along with the expression of mTOR in macrophage cells, were also taken into consideration. The detrimental impact of bacterial burden on synovial joints was reduced by simultaneously inhibiting TLR2, TNF-α, and IL-1ß. Lowered IFN-γ decreases its sensitivity to STAT1 and lowered IL-6 reduces STAT3 expressions. Whereas, elevated IL-10 enhances SOSC3 expression, which thereby able to limits STAT1/STAT3 inter-conversion. As a result, NF-κB activity was downregulated.

Toll-like receptor-2 in cardiomyocytes and macrophages mediates isoproterenol-induced cardiac inflammation and remodeling.

Heart failure (HF) is the leading cause of morbidity and mortality worldwide. Activation of the innate immune system initiates an inflammatory response during cardiac remodeling induced by isoproterenol (ISO). Here, we investigated whether Toll-like receptor-2 (TLR2) mediates ISO-induced inflammation, hypertrophy, and fibrosis. TLR2 was found to be increased in the heart tissues of mouse with HF under ISO challenge. Further, cardiomyocytes and macrophages were identified as the main cellular sources of the increased TLR2 levels in the model under ISO stimulation. The effect of TLR2 deficiency on ISO-induced cardiac remodeling was determined using TLR2 knockout mice and bone marrow transplantation models. In vitro studies involving ISO-treated cultured cardiomyocytes and macrophages showed that TLR2 knockdown significantly decreased ISO-induced cell inflammation and remodeling via MAPKs/NF-κB signaling. Mechanistically, ISO significantly increased the TLR2-MyD88 interaction in the above cells in a TLR1-dependent manner. Finally, DAMPs, such as HSP70 and fibronectin 1 (FN1), were found to be released from the cells under ISO stimulation, which further activated TLR1/2-Myd88 signaling and subsequently activated pro-inflammatory cytokine expression and cardiac remodeling. In summary, our findings suggest that TLR2 may be a target for the alleviation of chronic adrenergic stimulation-associated HF. In addition, this paper points out the possibility of TLR2 as a new target for heart failure under ISO stimulation.

Destabilization of fear memory by Rac1-driven engram-microglia communication in hippocampus.

Rac1 is a key regulator of the cytoskeleton and neuronal plasticity, and is known to play a critical role in psychological and cognitive brain disorders. To elucidate the engram specific Rac1 signaling in fear memory, a doxycycline (Dox)-dependent robust activity marking (RAM) system was used to label dorsal dentate gyrus (DG) engram cells in mice during contextual fear conditioning. Rac1 mRNA and protein levels in DG engram cells were peaked at 24 h (day 1) after fear conditioning and were more abundant in the fear engram cells than in the non-engram cells. Optogenetic activation of Rac1 in a temporal manner in DG engram cells before memory retrieval decreased the freezing level in the fear context. Optogenetic activation of Rac1 increased autophagy protein 7 (ATG7) expression in the DG engram cells and activated DG microglia. Microglia-specific transcriptomics and fluorescence in situ hybridization revealed that overexpression of ATG7 in the fear engram cells upregulated the mRNA of Toll-like receptor TLR2/4 in DG microglia. Knockdown of microglial TLR2/4 rescued fear memory destabilization induced by ATG7 overexpression or Rac1 activation in DG engram cells. These results indicate that Rac1-driven communications between engram cells and microglia contributes to contextual fear memory destabilization, and is mediated by ATG7 and TLR2/4, and suggest a novel mechanistic framework for the cytoskeletal regulator in fear memory interference.

FURIN, IFNL4, and TLR2 gene polymorphisms in relation to COVID-19 severity: a case-control study in Egyptian patients.

BACKGROUND AND AIM: A wide range of clinical manifestations and outcomes, including liver injury, have been reported in COVID-19 patients. We investigated the association of three substantial gene polymorphisms (FURIN, IFNL4, and TLR2) with COVID-19 disease susceptibility and severity to help predict prognosis. METHODS: 150 adult COVID-19-assured cases were categorized as follows: 78 patients with a non-severe presentation, 39 patients with severe disease, and 33 critically ill patients. In addition, 74 healthy controls were included. Clinical and laboratory evaluations were carried out, including complete and differential blood counts, D-dimer, lactate dehydrogenase (LDH), C-reactive protein (CRP), procalcitonin, ferritin, interleukin-6 (Il-6), and liver and kidney functions. FURIN (rs6226), IFNL4 (rs12979860), and TLR2 (rs3804099) genotyping allelic discrimination assays were conducted using real-time PCR. RESULTS: The FURIN, IFNL4, and TLR2 genotypes and their alleles differed significantly between COVID-19 patients and controls, as well as between patients with severe or critical illness and those with a non-severe presentation. According to a multivariable regression analysis, FURIN (C/T + T/T) and TLR2 (T/C + C/C) mutants were associated with COVID-19 susceptibility, with odds ratios of 3.293 and 2.839, respectively. FURIN C/C and IFNL4 T/T mutants were significantly linked to severe and critical illnesses. Multivariate regression analysis showed that FURIN (G/C + C/C) genotypes and IFNL4 T/T homozygosity were independent risk factors associated with increased mortality. CONCLUSION: FURIN, IFNL4, and TLR2 gene variants are associated with the risk of COVID-19 occurrence as well as increased severity and poor outcomes in Egyptian patients.

Simplified scalable synthesis of a water-soluble toll-like receptor 2 agonistic lipopeptide adjuvant for use with protein-based viral vaccines.

Toll-like receptors (TLRs) form a key bridge between the innate and adaptive immune systems. The lipopeptide based TLR2 agonists such as Pam2CSK4 are promising vaccine adjuvants but drawbacks include its surfactant like nature and cumbersome synthesis. Although the TLR2 activity of Pam2CS-OMe is commensurate with Pam2CSK4, its water solubility is much less, rendering it ineffective for clinical use. In the present investigation, we designed a synthesis pathway for a novel water-soluble TLR2-active analogue, Pam2CS-DMAPA (13), which enhanced the immunogenicity of recombinant SARS-CoV2 and hepatitis B antigens in mice. Co-formulation of compound 13 with 2 % aluminium hydroxide gel led to a further significant improvement in vaccine immunogenicity. This synthetically simpler compound 13 was water soluble and equally potent to Pam2CSK4 adjuvant, but was superior in terms of manufacturing simplicity and scalability. This makes compound 13 a promising TLR2 targeted adjuvant for further development.

Genetic polymorphisms of TLR1, TLR2, TLR3 and TLR4 in patients with recurrent or severe infections.

Toll-like receptors (TLRs) play an important role in innate immunity. Previous studies have shown that single nucleotide polymorphisms (SNPs) in the genes coding for these innate immune molecules can affect susceptibility to and the outcome of certain diseases. The aim of the present study was to examine the clinical relevance of well-studied TLR1-4 SNPs in individuals who are prone to infections. Four functional SNPs, TLR1 rs5743618 (1805C > A, Ser602Ile), TLR2 rs5743708 (2258G > A, Arg753Gln), TLR3 rs3775291 (1234C > T, Leu412Phe) and TLR4 rs4986790 (896A > G, Asp299Gly), were analysed in 155 patients with recurrent respiratory infections (n = 84), severe infections (n = 15) or common variable immunodeficiency (n = 56), and in 262 healthy controls, using the High Resolution Melting Analysis method. Polymorphisms of TLR2 rs5743708 (odds ratio [OR] 3.16; 95% confidence interval [CI] 1.45-6.83, p = .004, ap = .016) and TLR4 rs4986790 (OR 1.8; 95% CI 1.05-3.12, p = .028, ap = .112) were more frequent in patients with recurrent or severe infections than in controls. Interestingly, seven patients were found to carry both variant genotypes of TLR2 and TLR4, whereas none of the control group carried such genotypes (p  ≤ .0001). Moreover, TLR2 polymorphism was associated with increased risk for acute otitis media episodes (OR, 3.02; 95% CI 1.41-6.47; p = .012). This study indicates that children and adults who are more prone to recurrent or severe respiratory infections carry one or both variant types of TLR2 and TLR4 more often than control subjects. Genetic variations of TLRs help explain why some children are more susceptible to respiratory infections.

Endoplasmic reticulum stress is upregulated in inflammatory bowel disease and contributed TLR2 pathway-mediated inflammatory response.

OBJECTIVE: Endoplasmic reticulum stress (ERS) and Toll-like receptor 2 (TLR2) signaling play an important role in inflammatory bowel disease (IBD); however, the link between TLR2 and ERS in IBD is unclear. This study investigated whether Thapsigargin (TG) -induced ER protein expression levels contributed to TLR2-mediated inflammatory response. METHODS: The THP-1 cells were treated with TLR2 agonist (Pam3CSK4), ERS inducer Thapsigargin (TG) or inhibitor (TUDCA). The mRNA expressions of TLR1-TLR10 were detected by qPCR. The production and secretion of inflammatory factors were detected by PCR and ELISA. Immunohistochemistry was used to detect the expressions of GRP78 and TLR2 in the intestinal mucosa of patients with Crohn's disease (CD). The IBD mouse model was established by TNBS in the modeling group. ERS inhibitor (TUDCA) was used in the treatment group. RESULTS: The expression of TLRs was detected via polymerase chain reaction (PCR) in THP-1 cells treated by ERS agonist Thapsigargin (TG). According to the findings, TG could promote TLR2 and TLR5 expression. Subsequently, in TLR2 agonist Pam3CSK4 induced THP-1 cells, TG could lead to increased expression of the inflammatory factors such as TNF-α, IL-1ß and IL-8, and ERS inhibitor (TUDCA) could block this effect. However, Pam3CSK4 did not significantly impact the GRP78 and CHOP expression. Based upon the immunohistochemical results, TLR2 and GRP78 expression were significantly increased in the intestinal mucosa of patients with Crohn's disease (CD). For in vivo experiments, TUDCA displayed the ability to inhibit intestinal mucosal inflammation and reduce GRP78 and TLR2 proteins. CONCLUSIONS: ERS and TLR2 is upregulated in inflammatory bowel disease, ERS may promote TLR2 pathway-mediated inflammatory response. Moreover, ERS and TLR2 signaling could be novel therapeutic targets for IBD.

Malassezia globosa Induces Differentiation of Pathogenic Th17 Cells by Inducing IL-23 Secretion by Keratinocytes.

Malassezia, the most abundant fungal commensal on the mammalian skin, has been linked to several inflammatory skin diseases such as atopic dermatitis, seborrheic dermatitis and psoriasis. This study reveals that epicutaneous application with Malassezia globosa (M. globosa) triggers skin inflammation in mice. RNA-sequencing of the resulting mouse lesions indicates activation of Interleukin-17 (IL-17) signaling and T helper 17 (Th17) cells differentiation pathways by M. globosa. Furthermore, our findings demonstrate a significant upregulation of IL-23, IL-23R, IL-17A, and IL-22 expressions, along with an increase in the proportion of Th17 and pathogenic Th17 cells in mouse skin exposed to M. globosa. In vitro experiments illustrate that M. globosa prompts human primary keratinocytes to secrete IL-23 via TLR2/MyD88/NF-κB signaling. This IL-23 secretion by keratinocytes is shown to be adequate for inducing the differentiation of pathogenic Th17 cells in the skin. Overall, these results underscore the significant role of Malassezia in exacerbating skin inflammation by stimulating IL-23 secretion by keratinocytes and promoting the differentiation of pathogenic Th17 cells.

Serum TLR2 and TLR9 in Prostate Cancer Patients in Relation to EBV Status.

The relationship between Toll-like receptors (TLRs) and prostate cancer (PCa) is complex due to the presence of the Epstein-Barr virus (EBV) infection, which has been identified as a predisposing factor for some cancers, including PCa. The present study aims to investigate these complex links by examining the levels of selected TLRs and the potential impact of EBV infection on PCa. Therefore, we examined the serum of patients with PCa. The study compared EBV(+) patients to risk groups, the Gleason score (GS), and the T-trait. Additionally, the correlation between TLR and antibody levels was examined. The results indicated that higher levels of TLR-2 and TLR-9 were observed in more advanced PCa. The findings of this study may contribute to a deeper understanding of the role of viral infections in PCa and provide information on future strategies for the diagnosis, prevention, and treatment of these malignancies.

New Horizons in the Diagnosis of Gastric Cancer: The Importance of Selected Toll-like Receptors in Immunopathogenesis Depending on the Stage, Clinical Subtype, and Gender of Newly Diagnosed Patients.

INTRODUCTION: Toll-like receptors (TLRs) play a vital role in the innate immune response, recognizing pathogens and initiating the inflammatory response. Research suggests that TLRs may also have a significant impact on the development and progression of cancers, including gastric cancer (GC). Understanding the role of individual TLRs in the immunopathogenesis of gastric cancer may provide new information necessary to develop more effective diagnostic and therapeutic methods. AIM OF THE STUDY: This study aimed to determine the role of selected TLR-2, -3, -4, and -9 in the immunopathogenesis of patients with newly diagnosed and untreated gastric cancer. MATERIALS AND METHODS: The study included 60 newly diagnosed, untreated GC patients and 25 healthy volunteers. The research included analyses assessing the percentage of the tested TLRs on T and B lymphocyte subpopulations using multicolor flow cytometry and assessing their concentration in the serum of the examined patients using ELISA tests. The statistical analyses performed included a comparison of patients in individual stages of gastric cancer, an analysis of the most common clinical subtypes of gastric cancer, and a comparative analysis of differences in the gender of recruited patients. RESULTS: Our studies showed different expression levels of TLR-2, -3, -4, and -9 on T and B lymphocyte subpopulations, as well as their different concentrations in patients' serum. Significant differences in the expression of these receptors were observed depending on the stage of gastric cancer and its clinical subtypes. These differences were also visible in the context of patient gender. SUMMARY: The results of our studies suggest that TLR-2, -3, -4, and -9 may play an important role in the immunopathogenesis of gastric cancer. The differential expression of these receptors depending on the stage of the disease, clinical subtype, and gender of patients may have potential diagnostic and therapeutic significance. Further research is necessary to understand better the mechanisms of action of TLRs in gastric cancer and to apply this knowledge in clinical practice.

Variants rs3804099 and rs3804100 in the TLR2 Gene Induce Different Profiles of TLR-2 Expression and Cytokines in Response to Spike of SARS-CoV-2.

The present study aimed to identify in patients with severe COVID-19 and acute respiratory distress syndrome (ARDS) the association between rs3804099 and rs3804100 (TLR2) and evaluate the expression of TLR-2 on the cell surface of innate and adaptive cells of patients' carriers of C allele in at least one genetic variant. We genotyped 1018 patients with COVID-19 and ARDS. According to genotype, a subgroup of 12 patients was selected to stimulate peripheral blood mononuclear cells (PBMCs) with spike and LPS + spike. We evaluated soluble molecules in cell culture supernatants. The C allele in TLR2 (rs3804099, rs3804100) is not associated with a risk of severe COVID-19; however, the presence of the C allele (rs3804099 or rs3804100) affects the TLR-2 ability to respond to a spike of SARS-CoV-2 correctly. The reference group (genotype TT) downregulated the frequency of non-switched TLR-2+ B cells in response to spike stimulus; however, the allele's C carriers group is unable to induce this regulation, but they produce high levels of IL-10, IL-6, and TNF-α by an independent pathway of TLR-2. Findings showed that TT genotypes (rs3804099 and rs3804100) affect the non-switched TLR-2+ B cell distribution. Genotype TT (rs3804099 and rs3804100) affects the TLR-2's ability to respond to a spike of SARS-CoV-2. However, the C allele had increased IL-10, IL-6, and TNF-α by stimulation with spike and LPS.