Activation of Toll-like receptor 2 promotes mesenchymal stem/stromal cell-mediated immunoregulation and angiostasis through AKR1C1.

Background: Mesenchymal stem/stromal cells (MSCs) maintain tissue homeostasis in response to microenvironmental perturbations. Toll-like receptors (TLRs) are key sensors for exogenous and endogenous signals produced during injury. In this study, we aimed to investigate whether TLRs affect the homeostatic functions of MSCs after injury. Methods: We examined the expression of TLR2, TLR3 and TLR4 in MSCs, and analyzed the functional significance of TLR2 activation using single-cell RNA sequencing. Additionally, we investigated the effects and mechanisms of TLR2 and its downstream activation in MSCs on the MSCs themselves, on monocytes/macrophages, and in a mouse model of sterile injury-induced inflammatory corneal angiogenesis. Results: MSCs expressed TLR2, which was upregulated by monocytes/macrophages. Activation of TLR2 in MSCs promoted their immunoregulatory and angiostatic functions in monocytes/macrophages and in mice with inflammatory corneal angiogenesis, whereas TLR2 inhibition attenuated these functions. Single-cell RNA sequencing revealed AKR1C1, a gene encoding aldo-keto reductase family 1 member C1, as the most significantly inducible gene in MSCs upon TLR2 stimulation, though its stimulation did not affect cell compositions. AKR1C1 protected MSCs against ferroptosis, increased secretion of anti-inflammatory cytokines, and enhanced their ability to drive monocytes/macrophages towards immunoregulatory phenotypes, leading to the amelioration of inflammatory corneal neovascularization in mice. Conclusion: Our findings suggest that activation of TLR2-AKR1C1 signaling in MSCs serves as an important pathway for the survival and homeostatic activities of MSCs during injury.

Impact of Morphine withdrawal on genes related to the TLR2 pathway expressed in the Prefrontal Cortex.

Millions of people suffer from opioid use disorder, because of the ongoing opioid epidemic. The aversive symptoms of withdrawal are a leading factor for drug relapses, yet there are limited therapeutic options to minimize or prevent withdrawal symptoms. The mechanism behind opioid withdrawal is still not fully understood, thus preventing the development of new therapeutics. This study is an extension of our previously proposed mechanism of a toll-like receptor 2 (TLR2) mediated withdrawal response as a result of morphine induced microbial change that occurs during morphine withdrawal. Transcriptome analysis of the pre-frontal cortex indicated that there was increased expression of genes related to TLR2 signaling in morphine withdrawal treated animals compared to placebo controls. Antibiotic treatment further altered TLR2 related genes, recovering some of the morphine induced effect and leading to additional suppression of some genes related to the TLR2 pathway. Morphine withdrawal induced gene expression was attenuated in a whole body TLR2 knockout model. These results provide more support that TLR2 plays an integral role in morphine withdrawal mechanisms and could be a potential therapeutic target to minimize opioid withdrawal associated co-morbidities.

Effects of toll like receptor 4 (TLR4) and toll like receptor 2 (TLR 2) gene polymorphisms on clinical outcomes in acute non-biliary pancreatitis patients.

Introduction: In this retrospective study, it was aimed to evaluate effects of Toll Like Receptor 4 (TLR4) and Toll Like Receptor 2 (TLR 2) gene polymorphisms on clinical outcomes in acute non-biliary pancreatitis patients. Methods: A total of 108 acute non-biliary pancreatitis patients (ANBP) were retrospectively subjected to the study. Gender, age, number of attacks, hospitalization duration, amylase, lipase, aspartate aminotransferase (AST), alanine aminotransferase (ALT), leukocyte, C-reactive protein (CRP), total bilirubin, direct bilirubin, Atlanta score, ultrasonography (USG), Computer Tomography (CT) and patient outcome differences between TLR 4 Rs4986790, TLR 4 Rs4986791 and TLR 2 groups were evaluated. Results: According to TLR 4 Rs4986790 groups, females were significantly common in AA sequence (AA) group with statistically significant difference (p<0.05). Leukocyte mean of AG sequence (AG) group was significantly higher than of AA group (p<0.05). All parameter differences between TLR 4 Rs4986791 and TLR 2 groups were statistically insignificant (p>0.05). there was a statistically significant correlation between TLR 4 Rs4986790 and gender (r=0.265; p<0.01), Leukocyte (r=0.200; p<0.05) and Pseudocyst (r=0.203; p<0.05). TLR 4 Rs4986790 gene polymorphism had significant effect on leukocyte level in acute non-biliary pancreatitis patients (OR: -0.1.900; p<0.05). Predictive value of leukocyte for TLR 4 Rs4986790 was statistically significant (Area Under Curve: 0.624; p<0.05). For 7.65 leukocyte cut off value, sensitivity for AA gene polymorphism was 84.2% and specificity was 40.5. Conclusion: Although the clinical and outcome parameters of ANBP patients in terms of TLR 4 Rs4986791 and TLR 2 do not show significant differences, research findings point to the diagnostic value of patients' leukocyte parameters in determining TLR-4 Rs4986790 ploimorphism groups.

Distinct maturation, glucose metabolism, and inflammatory function of human monocytes-derived IDECs mediated by anti-IgE and Pam3CSK4 alone or in combination.

Background: Cell energy metabolism controls the activation and function of dendritic cells (DCs). Inflammatory dendritic epidermal cells (IDECs) in skin lesions of atopic dermatitis (AD) express high-affinity IgE receptor (FcϵRI) and toll-like receptor 2 (TLR2), which mediate the generation and maintenance of inflammation. However, cellular energy metabolism and effector function of IDECs mediated by FcϵRI and TLR2 have not been fully elucidated. Methods: IDECs in vitro were treated with TLR2 agonist Pam3CSK4 and anti-IgE alone or in combination for 24 h. Further, we analyzed the expression of cell surface activation markers, production of inflammatory factors, and cellular energy metabolism profiles of IDECs by using flow cytometry, multiplex assay, RNA sequencing, targeted energy metabolism, and seahorse assays. Results: Compared to the unstimulated or anti-IgE groups, Pam3CSK4 alone or combined with anti-IgE groups significantly increased the expression of CD80, CD83, and CD86 on IDECs, but did not affect the expression of the above markers in the anti-IgE group. The release of inflammatory cytokines increased in the Pam3CSK4 alone or combined with anti-IgE groups, while there was a weak increasing trend in the anti-IgE group. The glycolysis/gluconeogenesis pathway of carbon metabolism was affected in all treatment groups. Furthermore, compared to the control group, we found a decrease in pyruvic acid, upregulation of PFKM, downregulation of FBP1, and increase in extracellular lactate, glycolysis rate, and glycolysis capacity after all treatments, while there was no difference between each treatment group. However, there was no difference in glycolytic reserve and mitochondrial basic and maximum respiration among all groups. Conclusion: Our results indicate that glycolysis of IDECs may be activated through FcϵRI and TLR2 to upregulate inflammatory factors, suggesting that danger signals from bacteria or allergens might evoke an inflammatory response from AD through the glycolysis pathway.

Exosomal GDNF from Bone Marrow Mesenchymal Stem Cells Moderates Neuropathic Pain in a Rat Model of Chronic Constriction Injury.

Both of exosomes derived from mesenchymal stem cells (MSCs) and glial cell line-derived neurotrophic factor (GDNF) show potential for the treatment of neuropathic pain. Here, the analgesic effects of exosomes derived from bone marrow MSCs (BMSCs) were investigated. BMSCs-derived exosomes were isolated and characterized. Chronic constriction injury (CCI) was constructed to induce neuropathic pain in rats, which were then treated with exosomes. Pain behaviors were evaluated by measuring paw withdrawal thresholds and latency. The changes of key proteins, including cytokines, were explored using Western blot and ELISA. Administration of BMSCs-derived exosomes alleviated neuropathic pain, as demonstrated by the decrease of thermal hyperalgesia and mechanical allodynia, as well as the reduced secretion of pro-inflammatory cytokines in CCI rats. These effects were comparable to the treatment of GDNF alone. Mechanically, the exosomes suppressed the CCI-induced activation of TLR2/MyD88/NF-κB signaling pathway, while GDNF knockdown impaired their analgesic effects on CCI rat. BMSCs-derived exosomes may alleviate CCI-induced neuropathic pain and inflammation in rats by transporting GDNF.

Identification and analysis of oxidative stress-related genes in hypoxic-ischemic brain damage using bioinformatics and experimental verification.

BACKGROUND: Oxidative stress (OS) plays a major role in the progress of hypoxic-ischemic brain damage (HIBD). This study aimed to investigate OS-related genes and their underlying molecular mechanisms in neonatal HIBD. METHODS: Microarray data sets were acquired from the Gene Expression Omnibus (GEO) database to screen the differentially expressed genes (DEGs) between control samples and HIBD samples. OS-related genes were drawn from GeneCards and OS-DEGs in HIBD were obtained by intersecting with the DEGs. Subsequently, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene Set Enrichment Analysis (GSEA) were conducted to determine the underlying mechanisms and functions of OS-DEGs in HIBD. Moreover, the hub genes were screened using the protein-protein interaction network and identified in the GSE144456 data set. CIBERSORT was then performed to evaluate the expression of immunocytes in each sample and perform a correlation analysis of the optimal OS-DEGs and immunocytes. Finally, quantitative reverse transcription polymerase chain reaction (RT-qPCR) and immunohistochemistry were performed to validate the expression levels of the optimal OS-DEGs. RESULTS: In total, 93 OS-DEGs were identified. GO, KEGG, and GSEA enrichment analyses indicated that these genes were predominantly enriched in OS and inflammation. Four OS-related biomarker genes (Jun, Fos, Tlr2, and Atf3) were identified and verified. CIBERSORT analysis revealed the dysregulation of six types of immune cells in the HIBD group. Moreover, 47 drugs that might target four OS-related biomarker genes were screened. Eventually, RT-qPCR and immunohistochemistry results for rat samples further validated the expression levels of Fos, Tlr2, and Atf3. CONCLUSIONS: Fos, Tlr2 and Atf3 are potential OS-related biomarkers of HIBD progression. The mechanisms of OS are associated with those of neonatal HIBD.

TLR2 Derangements Likely Play a Significant Role in the Inflammatory Response and Thrombosis in Patients with Ph(-) Classical Myeloproliferative Neoplasm.

We investigated the role of toll-like receptors (TLRs) in inflammatory pathways in Philadelphia chromosome-negative myeloproliferative neoplasms (Ph(-)MPNs). TLR2 expression was increased in ET, PV, and MPN (grouped as (PV + (ET) + MF)), whereas TLR4 was elevated only in MPN. TLR3, 7, and 9 were not elevated. Cultured monocyte-derived dendritic cells and plasma assays in TLR2-elevated patients were found to secrete more cytokines than those from TLR2-normal patients. These facts suggest that TLR2 is the major inflammatory pathways in MPN. We also measured S100A9 and reactive oxygen species (ROS), revealing increased S100A9 in PV, MF, and MPN, while ROS were only increased in MF. These data suggests that MPNs initially involve TLR2, with minor contributions from TLR4, and with S100A9, leading to ROS formation, JAK2 mutation, and progression to MF or leukemia. Furthermore, patients with JAK2 mutations or leukocytosis exhibited higher TLR2 expression. In leukocyte-platelet interactions, cells from MPN patients displayed a stronger response to a TLR2 agonist than TLR4 agonist. A TLR2 inhibitor (but not a TLR4 inhibitor) attenuated this response. Thrombosis incidence was higher in TLR2-elevated patients (29%) than in TLR2-normal patients (19%). These findings suggest that TLR2 likely contributes to thrombosis in MPN.

Catabolic mediators from TLR2-mediated proteoglycan aggrecan peptide-stimulated chondrocytes are reduced by Lactobacillus-conditioned media.

In osteoarthritis (OA), extracellular matrix (ECM) digestion by cartilage-degrading enzymes drives cartilage destruction and generates ECM fragments, such as proteoglycan aggrecan (PG) peptides. PG peptides have been shown to induce immunological functions of chondrocytes. However, the role of PG peptides in stimulating catabolic mediators from chondrocytes has not been investigated. Therefore, we aim to determine the effects and its mechanism by which PG peptides induce chondrocytes to produce catabolic mediators in OA. Human chondrocytes were stimulated with IFNγ and various PG peptides either (i) with or (ii) without TLR2 blockade or (iii) with Lactobacillus species-conditioned medium (LCM), a genus of bacteria with anti-inflammatory properties. Transcriptomic analysis, cartilage-degrading enzyme production and TLR2-intracellular signaling activation were investigated. Chondrocytes treated with PG peptides p16-31 and p263-280 increased expression levels of genes associated with chondrocyte hypertrophy, cartilage degradation and proteolytic enzyme production. TLR2 downstream signaling proteins (STAT3, IkBα and MAPK9) were significantly phosphorylated in p263-280 peptide-stimulated chondrocytes. MMP-1 and ADAMTS-4 were significantly reduced in p263-280 peptides-treated condition with TLR2 blockade or LCM treatment. Phosphorylation levels of IkBa, ERK1/2 and MAPK9 were significantly decreased with TLR2 blockade, but only phosphorylation levels of MAPK9 was significantly decreased with LCM treatment. Our study showed that PG peptide stimulation via TLR2 induced cartilage-degrading enzyme production via activation of MAPK, NFκB and STAT3 pathways.

The Impact of Extracellular Histones and Absence of Toll-like Receptors on Cardiac Functional and Electrical Disturbances in Mouse Hearts.

In polymicrobial sepsis, the extracellular histones, mainly released from activated neutrophils, significantly contribute to cardiac dysfunction (septic cardiomyopathy), as demonstrated in our previous studies using Echo-Doppler measurements. This study aims to elucidate the roles of extracellular histones and their interactions with Toll-like receptors (TLRs) in cardiac dysfunction. Through ex vivo assessments of ECG, left ventricle (LV) function parameters, and in vivo Echo-Doppler studies in mice perfused with extracellular histones, we aim to provide comprehensive insights into the mechanisms underlying sepsis-induced cardiac dysfunction. Langendorff-perfused hearts from both wild-type and TLR2, TLR3, or TLR4 knockout (KO) mice were examined. Paced mouse hearts were perfused with histones to assess contractility and relaxation. Echo-Doppler studies evaluated cardiac dysfunction after intravenous histone injection. Histone perfusion caused defects in contractility and relaxation, with TLR2 and TLR3 KO mice being partially protected. Specifically, TLR2 KO mice exhibited the greatest reduction in Echo-Doppler abnormalities, while TLR4 KO exacerbated cardiac dysfunction. Among individual histones, H1 induced the most pronounced abnormalities in cardiac function, apoptosis of cardiomyocytes, and LDH release. Our data highlight significant interactions between histones and TLRs, providing insights into histones especially H1 as potential therapeutic targets for septic cardiomyopathy. Further studies are needed to explore specific histone-TLR interactions and their mechanisms.

Levilactobacillus brevis IBARAKI-TS3 Isolated From Pickles Promotes Production of Interleukin-10 via Toll-Like Receptor 2 in Human M2 Macrophages.

M2 macrophages play an important role in food allergy. Several studies have reported that lactic acid bacteria isolated from pickles exert antiallergic effects. We investigated the effects of several strains of lactic acid bacteria on the immune function of M2 macrophages. M2 macrophages differentiated from THP-1 cell line by interleukin-4 (IL-4) and IL-13 strongly expressed CD163, CD206, and HMOX1 mRNA. Levilactobacillus brevis IBARAKI-TS3 (IBARAKI-TS3) isolated from pickles was identified as a lactic acid bacterium that enhances the expressions of IL-10 and EBI3 mRNA in M2 macrophages. IBARAKI-TS3 induced the expression of genes involved in Toll-like receptor (TLR) signaling, such as IRAK, mitogen-activated protein kinases (MAPKs), and NF-κB mRNA. IBARAKI-TS3-induced IL-10 production was suppressed by anti-TLR2-neutralizing antibodies. Furthermore, the IBARAKI-TS3-induced increase in IL-10 levels was significantly reduced in TLR2-knockdown M2 macrophages compared to M2 macrophages. These results suggest that IBARAKI-TS3 promotes of IL-10 production via TLR2 in M2 macrophages.

Probiotics suppress LL37 generated rosacea-like skin inflammation by modulating the TLR2/MyD88/NF-κB signaling pathway.

Rosacea, a chronic inflammatory dermatological condition, is characterized by facial erythema and pustules. Recent investigations have delved into the interplay between the gut microbiota and rosacea pathogenesis, unveiling promising avenues for therapeutic intervention. In this study, we screened and isolated strains Ligilactobacillus salivarius 23-006 and Lacticaseibacillus paracasei 23-008 from the feces of healthy volunteers and evaluated the intervention effects of probiotics on rosacea by constructing an LL37 induced rosacea-like mouse model. Our results showed that both L. salivarius 23-006 and L. paracasei 23-008 were probiotic strains with favourable properties. In specific, we observed that both L. salivarius 23-006 and L. paracasei 23-008 alleviated skin lesions, reduced skin inflammatory infiltrates, and decreased the expression of inflammatory factors in mice, with the combination of L. salivarius 23-006 and L. paracasei 23-008 having the most significant effect. Moreover, the combination of strains reduced the expression of cathelicidin LL37 and rosacea-associated factors by inhibiting the TLR2/MyD88/NF-κB pathway. The 16S rRNA analysis showed that the combination enhanced the intestinal barrier, restored intestinal microbiota homeostasis, and up-regulated the abundance of Lactobacillus while down-regulating the abundance of Coprococcus and Oscillospira. We also explored the effects of postbiotics of L. salivarius 23-006 and L. paracasei 23-008 on rosacea. While postbiotics could also ameliorate the rosacea-like phenotype in mice via the TLR2/MyD88/NF-κB pathway, the effects were not as pronounced as those observed with probiotic treatment. However, the postbiotics still enhanced the intestinal barrier, up-regulated the Lactobacillus abundance, and modulated the intestinal microbiota. In conclusion, our study revealed that L. salivarius 23-006 and L. paracasei 23-008 improved rosacea by regulating the TLR2/MyD88/NF-κB pathway and intestinal microbiota, providing a theoretical basis for the treatment of rosacea.

Novel Small Molecules with Anti-Inflammatory and Anti-Angiogenic Activity in a Mouse Model of Oxygen-Induced Retinopathy.

Retinopathy of prematurity (ROP) has a dual-phase disease pathology; in phase 1, hyperoxia-induced vaso-obliteration occurs in the retinal vasculature due to increased oxidative stress (OS) and inflammation, followed by phase 2, where hypoxia increases the overproduction of growth factors, inducing retinal neovascularization. Toll-like receptor 2 and -4 (TLR2 and TLR4) overactivation, hyper-inflammation, macrophages, and neutrophil infiltration contribute to the developing ROP. AVR-121 and AVR-123 are novel classes of small-molecule dual inhibitors of TLR2/4 tested in a human leukemia monocytic cell line (THP-1) and cord-blood-derived mononuclear cells (CBMCs). Both compounds inhibited TLR2/4 signaling-related inflammatory cytokines in THP-1 cells and inhibited VEGF-induced neovascularization in human retinal endothelial cells (HRECs), which are hallmarks of ROP. In an oxygen-induced retinopathy (OIR) murine model, the intraperitoneal injection of AVR-123 in the hyperoxia phase (P7-P12) or a nanosuspension eyedrop of AVR-123 in the hypoxic phase (P12-P17) significantly reduced vaso-obliteration, angiogenesis, and inflammatory cytokine profiles while not inhibiting the necessary growth factor VEGF in the juvenile mouse eyes. The results are consistent with our hypothesis that targeting the dual TLR2/4 pathway will reduce inflammation, angiogenesis, and vaso-obliteration in vitro and in vivo and reduce cytotoxic immune cells. AVR-123 has the potential to be developed as a therapy for ROP.

Bioactive Compounds and Probiotics Mitigate Mastitis by Targeting NF-κB Signaling Pathway.

Mastitis is a significant inflammatory condition of the mammary gland in dairy cows. It is caused by bacterial infections and leads to substantial economic losses worldwide. The disease can be either clinical or sub-clinical and presents challenges such as reduced milk yield, increased treatment costs, and the need to cull affected cows. The pathogenic mechanisms of mastitis involve the activation of Toll-like receptors (TLRs), specifically TLR2 and TLR4. These receptors play crucial roles in recognizing pathogen-associated molecular patterns (PAMPs) and initiating immune responses through the NF-κB signaling pathway. Recent in vitro studies have emphasized the importance of the TLR2/TLR4/NF-κB signaling pathway in the development of mastitis, suggesting its potential as a therapeutic target. This review summarizes recent research on the role of the TLR2/TLR4/NF-κB signaling pathway in mastitis. It focuses on how the activation of TLRs leads to the production of proinflammatory cytokines, which, in turn, exacerbate the inflammatory response by activating the NF-κB signaling pathway in mammary gland tissues. Additionally, the review discusses various bioactive compounds and probiotics that have been identified as potential therapeutic agents for preventing and treating mastitis by targeting TLR2/TLR4/NF-κB signaling pathway. Overall, this review highlights the significance of targeting the TLR2/TLR4/NF-κB signaling pathway to develop effective therapeutic strategies against mastitis, which can enhance dairy cow health and reduce economic losses in the dairy industry.

Association of IL-9 Cytokines with Hepatic Injury in Echinococcus granulosus Infection.

Cystic echinococcosis (CE) is a zoonotic disease caused by the parasite Echinococcus granulosus (E. granulosus), which can lead to the formation of liver lesions. Research indicates that E. granulosus releases both Toll-like receptor 2 (TLR2) and Interleukin-9 (IL-9), which can potentially impair the body's innate immune defenses and compromise the liver's ability to fight against diseases. To investigate the role of TLR2 and IL-9 in liver damage caused by E. granulosus infection, samples were initially collected from individuals diagnosed with CE. Subsequently, BALB/c mice were infected with E. granulosus at multiple time points (4 weeks, 12 weeks, 32 weeks) and the expression levels of these markers was then assessed at each of these phases. Furthermore, a BALB/c mouse model was generated and administered anti-IL-9 antibody via intraperitoneal injection. The subsequent analysis focused on the TLR2/MyD88/NF-κB signaling pathway and the expression of IL-9 in E. granulosus was examined. A co-culture experiment was conducted using mouse mononuclear macrophage cells (RAW264.7) and hepatic stellate cells (HSCs) in the presence of E. granulosus Protein (EgP). The findings indicated elevated levels of IL-9 and TLR2 in patients with CE, with the activation of the signaling pathway significantly increased as the duration of infection progressed. Administration of anti-IL-9 in mice reduced the activation of the TLR2/MyD88/NF-κB signaling pathway, exacerbating liver injury. Moreover, EgP stimulates the TLR2/MyD88/NF-κB signaling pathway, resulting in the synthesis of α-SMA and Collagen I. The data suggest that infection with E. granulosus may stimulate the production of IL-9 through the activation of the TLR2/MyD88/NF-κB signaling pathway, which is mediated by TLR2. This activation stimulates RAW264.7 and HSCs, exacerbating liver injury and fibrosis.

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.

TLR2 immunotherapy suppresses neuroinflammation, tau spread, and memory loss in rTg4510 mice.

In Alzheimer's disease, chronic neuroinflammation is accompanied by amyloid and tau pathologies. Especially, aberrant microglial activation is known to precede the regional tau pathology development, but the mechanisms how microglia affect tau spread remain largely unknown. Here, we found that toll-like receptor 2 (TLR2) in microglia recognizes oligomeric tau as a pathogenic ligand and induces inflammatory responses. Knockout of TLR2 reduced tau pathology and microglial activation in rTg4510 tau transgenic mice. Treatment of oligomeric tau induced TLR2 activation and increased inflammatory responses in microglial cells. TLR2 further mediated the tau-induced microglial activation and promoted tau uptake into neurons in neuron-microglia co-culture system and in mouse hippocampus after intracranial tau injection. Importantly, treatment with anti-TLR2 monoclonal antibody Tomaralimab blocked TLR2 activation and inflammatory responses in a dose-dependent manner, and significantly reduced tau spread and memory loss in rTg4510 mice. These results suggest that TLR2 plays a crucial role in tau spread by causing aberrant microglial activation in response to pathological tau, and blocking TLR2 with immunotherapy may ameliorate tau pathogenesis in Alzheimer's disease.

Phospholipid peroxidation in macrophage confers tumor resistance by suppressing phagocytic capability towards ferroptotic cells.

Ferroptosis holds significant potential for application in cancer therapy. However, ferroptosis inducers are not cell-specific and can cause phospholipid peroxidation in both tumor and non-tumor cells. This limitation greatly restricts the use of ferroptosis therapy as a safe and effective anticancer strategy. Our previous study demonstrated that macrophages can engulf ferroptotic cells through Toll-like receptor 2 (TLR2). Despite this advancement, the precise mechanism by which phospholipid peroxidation in macrophages affects their phagocytotic capability during treatment of tumors with ferroptotic agents is still unknown. Here, we utilized flow sorting combined with redox phospholipidomics to determine that phospholipid peroxidation in tumor microenvironment (TME) macrophages impaired the macrophages ability to eliminate ferroptotic tumor cells by phagocytosis, ultimately fostering tumor resistance to ferroptosis therapy. Mechanistically, the accumulation of phospholipid peroxidation in the macrophage endoplasmic reticulum (ER) repressed TLR2 trafficking to the plasma membrane and caused its retention in the ER by disrupting the interaction between TLR2 and its chaperone CNPY3. Subsequently, this ER-retained TLR2 recruited E3 ligase MARCH6 and initiated the proteasome-dependent degradation. Using redox phospholipidomics, we identified 1-steaoryl-2-15-HpETE-sn-glycero-3-phosphatidylethanolamine (SAPE-OOH) as the crucial mediator of these effects. Conclusively, our discovery elucidates a novel molecular mechanism underlying macrophage phospholipid peroxidation-induced tumor resistance to ferroptosis therapy and highlights the TLR2-MARCH6 axis as a potential therapeutic target for cancer therapy.

An mRNA vaccine for pancreatic cancer designed by applying in silico immunoinformatics and reverse vaccinology approaches.

Pancreatic ductal adenocarcinoma is the most prevalent pancreatic cancer, which is considered a significant global health concern. Chemotherapy and surgery are the mainstays of current pancreatic cancer treatments; however, a few cases are suitable for surgery, and most of the cases will experience recurrent episodes. Compared to DNA or peptide vaccines, mRNA vaccines for pancreatic cancer have more promise because of their delivery, enhanced immune responses, and lower proneness to mutation. We constructed an mRNA vaccine by analyzing S100 family proteins, which are all major activators of receptors for advanced glycation end products. We applied immunoinformatic approaches, including physicochemical properties analysis, structural prediction and validation, molecular docking study, in silico cloning, and immune simulations. The designed mRNA vaccine was estimated to have a molecular weight of 165023.50 Da and was highly soluble (grand average of hydropathicity of -0.440). In the structural assessment, the vaccine seemed to be a well-stable and functioning protein (Z score of -8.94). Also, the docking analysis suggested that the vaccine had a high affinity for TLR-2 and TLR-4 receptors. Additionally, the molecular mechanics with generalized Born and surface area solvation analysis of the "Vaccine-TLR-2" (-141.07 kcal/mol) and "Vaccine-TLR-4" (-271.72 kcal/mol) complexes also suggests a strong binding affinity for the receptors. Codon optimization also provided a high expression level with a GC content of 47.04% and a codon adaptation index score 1.0. The appearance of memory B-cells and T-cells was also observed over a while, with an increased level of helper T-cells and immunoglobulins (IgM and IgG). Moreover, the minimum free energy of the mRNA vaccine was predicted at -1760.00 kcal/mol, indicating the stability of the vaccine following its entry, transcription, and expression. This hypothetical vaccine offers a groundbreaking tool for future research and therapeutic development of pancreatic cancer.

Impact of Toll-like receptor 2 (rs5743708) gene polymorphism in pediatric pneumonia: risk and severity.

Pediatric pneumonia is a common respiratory infection that affects children and is thought to be a major source of mortality and morbidity worldwide, particularly in low- and middle-income nations. Toll-like receptor2 (TLR2) is an important receptor involved in the recognition of bacterial pathogens and the activation of the immune response. Genetic variability in TLR2 may partially explain individual differences in susceptibility to infections. The purpose of this study was to investigate the possible contribution of the TLR2 (rs5743708) variant to the risk and severity of pediatric pneumonia infection. The study included 100 pediatric patients diagnosed with pneumonia and 100 normal controls who were age and gender matched. Real-time polymerase chain reaction (PCR) was used to genotype participants for the TLR2 (rs5743708) variant. The analysis revealed that children with the TLR2 (rs5743708) (G/A) genotype showed a 2.52-fold greater risk of having pneumonia (OR: 2.52; 95% CI: 1.32-4.79; p = 0.005) in comparison with patients who have wild homozygous genotypes. Furthermore, we observed that the TLR2 (rs5743708) (A) allele is connected to a greater risk of pneumonia infection in children (OR: 1.612; 95% CI: 1.07-2.43; p = 0.023) but did not significantly influence infection severity. In conclusion, children with the TLR2 (rs5743708) mutant (G/A) genotype and (A) allele had a significantly higher risk of having pneumonia, but they were not at high risk for the severity of the infection.

[Effect of oxymatrine on Cryptosporidium parvum infection in mice based on the HMGB1-TLR2/TLR4-NF-κB pathway].

OBJECTIVE: To investigate the involvement of the high mobility group box protein B1 (HMGB1)-Toll-like receptor 2 (TLR2)/TLR4-nuclear factor κB (NF-κB) pathway in the intestinal mucosal injury induced by Cryptosporidium parvum infection, and to examine the effect of oxymatrine (OMT) on C. parvum infection in mice. METHODS: Forty SPF 4-week-old BALB/c mice were randomly divided into four groups, including the control group, infection group, glycyrrhizin (GA) group and OMT group. Each mouse was orally administered with 1 × 105 C. parvum oocysts one week in the infection, GA and OMT groups following dexamethasone-induced immunosuppression to model C. parvum intestinal infections in mice. Upon successful modeling, mice in the GA group were intraperitoneally injected with GA at a daily dose of 25.9 mL/kg for successive two weeks, and animals in the OMT group were orally administered OMT at a daily dose of 50 mg/kg for successive two weeks, while mice in the control group were given normal food and water. All mice were sacrificed two weeks post-treatment, and proximal jejunal tissues were sampled. The pathological changes of mouse intestinal mucosal specimens were observed using hematoxylin-eosin (HE) staining, and the mouse intestinal villous height, intestinal crypt depth and the ratio of intestinal villous height to intestinal crypt depth were measured. The occludin and zonula occludens protein 1 (ZO1) expression was determined in mouse intestinal epithelial cells using immunohistochemistry, and the relative expression of HMGB1, TLR2, TLR4, myeloid differentiation primary response gene 88 (MyD88) and NF-κB p65 mRNA was quantified in mouse jejunal tissues using quantitative real-time PCR (qPCR) assay. RESULTS: HE staining showed that the mouse intestinal villi were obviously atrophic, shortened, and detached, and the submucosal layer of the mouse intestine was edematous in the infection group as compared with the control group, while the mouse intestinal villi tended to be structurally intact and neatly arranged in the GA and OMT groups. There were significant differences among the four groups in terms of the mouse intestinal villous height (F = 6.207, P = 0.000 5), intestinal crypt depth (F = 6.903, P = 0.000 3) and the ratio of intestinal villous height to intestinal crypt depth (F = 37.190, P < 0.000 1). The mouse intestinal villous height was lower in the infection group than in the control group [(321.9 ± 41.1) µm vs. (399.5 ± 30.9) µm; t = 4.178, P < 0.01] and the GA group [(321.9 ± 41.1) µm vs. (383.7 ± 42.7) µm; t = 3.130, P < 0.01], and the mouse intestinal crypt depth was greater in the infection group [(185.0 ± 35.9) µm] than in the control group [(128.4 ± 23.6) µm] (t = 3.877, P < 0.01) and GA group [(143.3 ± 24.7) µm] (t = 2.710, P < 0.05). The mouse intestinal villous height was greater in the OMT group [(375.3 ± 22.9) µm] than in the infection group (t = 3.888, P < 0.01), and there was no significant difference in mouse intestinal villous height between the OMT group and the control group (t = 1.989, P > 0.05). The mouse intestinal crypt depth was significantly lower in the OMT group [(121.5 ± 27.3) µm] than in the infection group (t = 4.133, P < 0.01), and there was no significant difference in mouse intestinal crypt depth between the OMT group and the control group (t = 0.575, P > 0.05). The ratio of the mouse intestinal villous height to intestinal crypt depth was significantly lower in the infection group (1.8 ± 0.2) than in the control group (3.1 ± 0.3) (t = 10.540, P < 0.01) and the GA group (2.7 ± 0.3) (t = 7.370, P < 0.01), and the ratio of the mouse intestinal villous height to intestinal crypt depth was significantly higher in the OMT group (3.1 ± 0.2) than in the infection group (t = 15.020, P < 0.01); however, there was no significant difference in the ratio of the mouse intestinal villous height to intestinal crypt depth between the OMT group and the control group (t = 0.404, P > 0.05). Immunohistochemical staining showed significant differences among the four groups in terms of occludin (F = 28.031, P < 0.000 1) and ZO1 expression (F = 14.122, P < 0.000 1) in mouse intestinal epithelial cells. The proportion of positive occluding expression was significantly lower in mouse intestinal epithelial cells in the infection group than in the control group [(14.3 ± 4.5)% vs. (28.3 ± 0.5)%; t = 3.810, P < 0.01], and the proportions of positive occluding expression were significantly higher in mouse intestinal epithelial cells in the GA group [(30.3 ± 1.3)%] and OMT group [(25.8 ± 1.5)%] than in the infection group (t = 7.620 and 5.391, both P values < 0.01); however, there was no significant differences in the proportion of positive occluding expression in mouse intestinal epithelial cells between the GA or OMT groups and the control group (t = 1.791 and 2.033, both P values > 0.05). The proportion of positive ZO1 expression was significantly lower in mouse intestinal epithelial cells in the infection group than in the control group [(14.4 ± 1.8)% vs. (24.2 ± 2.8)%; t = 4.485, P < 0.01], and the proportions of positive ZO1 expression were significantly higher in mouse intestinal epithelial cells in the GA group [(24.1 ± 2.3)%] (t = 5.159, P < 0.01) and OMT group than in the infection group [(22.5 ± 1.9)%] (t = 4.441, P < 0.05); however, there were no significant differences in the proportion of positive ZO1 expression in mouse intestinal epithelial cells between the GA or OMT groups and the control group (t = 0.037 and 0.742, both P values > 0.05). qPCR assay showed significant differences among the four groups in terms of HMGB1 (F = 21.980, P < 0.000 1), TLR2 (F = 20.630, P < 0.000 1), TLR4 (F = 17.000, P = 0.000 6), MyD88 (F = 8.907, P = 0.000 5) and NF-κB p65 mRNA expression in mouse jejunal tissues (F = 8.889, P = 0.000 7). The relative expression of HMGB1 [(5.97 ± 1.07) vs. (1.05 ± 0.07); t = 6.482, P < 0.05] 、TLR2 [(5.92 ± 1.29) vs. (1.10 ± 0.14); t = 5.272, P < 0.05] 、TLR4 [(5.96 ± 1.50) vs. (1.02 ± 0.03); t = 4.644, P < 0.05] 、MyD88 [(3.00 ± 1.26) vs. (1.02 ± 0.05); t = 2.734, P < 0.05] and NF-κB p65 mRNA [(2.33 ± 0.72) vs. (1.04 ± 0.06); t = 2.665, P < 0.05] was all significantly higher in mouse jejunal tissues in the infection group than in the control group. A significant reduction was detected in the relative expression of HMGB1 (0.63 ± 0.01), TLR2 (0.42 ± 0.10), TLR4 (0.35 ± 0.07), MyD88 (0.70 ± 0.11) and NF-κB p65 mRNA (0.75 ± 0.01) in mouse jejunal tissues in the GA group relative to the control group (t = 8.629, 5.830, 11.500, 4.729 and 6.898, all P values < 0.05), and the relative expression of HMGB1, TLR2, TLR4, MyD88 and NF-κB p65 mRNA significantly reduced in mouse jejunal tissues in the GA group as compared to the infection group (t = 7.052, 6.035, 4.084, 3.165 and 3.274, all P values < 0.05). In addition, the relative expression of HMGB1 (1.14 ± 0.60), TLR2 (1.00 ± 0.24), TLR4 (1.14 ± 0.07), MyD88 (0.96 ± 0.25) and NF-κ B p65 mRNA (1.12 ± 0.17) was significantly lower in mouse jejunal tissues in the OMT group than in the infection group (t = 7.059, 5.320, 3.510, 3.466 and 3.273, all P values < 0.05); however, there were no significant differences between the OMT and control groups in terms of relative expression of HMGB1, TLR2, TLR4, MyD88 or NF-κB p65 mRNA in mouse jejunal tissues (t = 0.239, 0.518, 1.887, 0.427 and 0.641, all P values > 0.05). CONCLUSIONS: C. parvum infection causes intestinal inflammatory responses and destruction of intestinal mucosal barrier through up-regulating of the HMGB1-TLR2/TLR4-NF-κB pathway. OMT may suppress the intestinal inflammation and repair the intestinal mucosal barrier through inhibiting the activity of the HMGB1-TLR2/TLR4-NF-κB pathway.