TLR2 agonist Pam3CSK4 enhances the antibacterial functions of GM-CSF induced neutrophils to methicillin-resistant Staphylococcus aureus

Mycobacterium tuberculosis specific protein Rv1509 modulates osteoblast and osteoclast differentiation via TLR2 signaling

Tuberculosis (TB), caused by Mycobacterium tuberculosis (M.tb), is one of the most ancient diseases recorded. In cases of bone TB, it significantly disrupts bone homeostasis, though the precise mechanisms are poorly understood and effective treatment targets are scarce. Our study investigated the role of Rv1509 in the pathogenesis of bone TB. We found that Rv1509 enhances the differentiation of bone marrow macrophages (BMMs) into osteoclasts by activating the TLR2 pathway, which stimulates the production of IL-6 and TNF-α. This, in turn, indirectly inhibits osteoblast differentiation and mineralization. Additionally, Rv1509 directly impairs osteoblast function and enhances the secretion of RANKL via TLR2 signaling, creating a detrimental RANKL/OPG imbalance that promotes osteoclast differentiation and bone degradation. Notably, the injection of Rv1509 into mouse skulls led to extensive bone damage, highlighting its significant role as a virulence factor in the pathogenesis of bone TB.

Zhike Erfang Alleviates MRSA-Induced Pneumonia by Inhibiting TRAF6 and Activating NLRP3 Inflammatory Body

Purpose

The therapeutic effects of Zhike Erfang in modulating the cellular responses and immune microenvironment associated with MRSA-induced acute lung injury remain unclear. This study aims to elucidate the potential mechanisms by which Zhike Erfang mitigate the cellular and molecular effects of MRSA in a laboratory model.

Patients and Methods

A mouse model of acute lung injury was established using heat-inactivated MRSA. Lung tissue and bronchoalveolar lavage fluid were collected for analysis. Macrophages were pretreated with Zhike Erfang for 30 minutes before exposure to heat-inactivated MRSA for 24 hours. Protein expressions of TRAF6, iNOS, TNF-α, IL-1β, NLRP3, and caspase-1 in lung tissues were quantified using Western blot. The content of LDH was detected by the lactate dehydrogenase cytotoxicity test kit.

Results

Zhike Erfang significantly reduced the expression of iNOS, LDH, TNF-α, IL-1β, NLRP3, and caspase-1 in a dose-dependent manner in lung tissues from the MRSA model. Zhike Erfang inhibited the expression of TRAF6.

Conclusion

Zhike Erfang can alleviate pneumonia caused by MRSA by inhibiting TRAF6 and inducing NLRP3 inflammatory body activation.

Exploration of the Potential Mechanism of Yujin Powder Treating Dampness-heat Diarrhea by Integrating UPLC-MS/MS and Network Pharmacology Prediction

BACKGROUND

Yujin powder (YJP) is a classic prescription for treating dampness-heat diarrhea (DHD) in Traditional Chinese Medicine (TCM), but the main functional active ingredients and the exact mechanisms have not been systematically studied.

OBJECTIVES

This study aimed to preliminarily explore the potential mechanisms of YJP for treating DHD by integrating UPLC-MS/MS and network pharmacology methods.

METHODS

Ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) technology was used to determine the ingredients of YJP. And then, the targets of these components were predicted and screened from TCMSP, SwissTargetPrediction databases. The disease targets related to DHD were obtained by using the databases of GeneCards, OMIM, DisGeNET, TTD, and DrugBank. The protein-protein interaction networks (PPI) of YJP-DHD were constructed using the STRING database and Origin 2022 software to identify the cross-targets by screening the core-acting targets and a network diagram by Cytoscape 3.8.2 software was also constructed. Metascape database was used for performing GO and KEGG enrichment anlysis on the core genes. Finally, molecular docking was used to verify the results with AutoDock 4.2.6, AutoDock Tools 1.5.6, PyMOL 2.4.0, and Open Babel 2.3.2 software.

RESULTS

597 components in YJP were detected, and 153 active components were obtained through database screening, among them the key active ingredients include coptisine, berberine, baicalein, etc. There were 362 targets treating DHD, among them the core targets included TNF, IL-6, ALB, etc. The enriched KEGG pathways mainly involve PI3K-Akt, TNF, MAPK, etc. Molecular docking results showed that coptisine, berberine, baicalein, etc., had a strong affinity with TNF, IL-6, and MAPK14. Therefore, TNF, IL-6, MAPK14, ALB, etc., are the key targets of the active ingredients of YJP coptisine, baicalein, and berberine, etc. They have the potential to regulate PI3K-Akt, MAPK, and TNF signalling pathways. The component-target-disease network diagram revealed that YJP treated DHD through the effects of anti-inflammation, anti-diarrhea, immunoregulation, and improving intestinal mucosal injury.

CONCLUSION

It is demonstrated that YJP treats DHD mainly through the main active ingredients coptisine, berberine, baicalein, etc. comprehensively exerting the effects of anti-inflammation, anti-diarrhea, immunoregulation, and improving intestinal mucosal injury, which will provide evidence for further in-depth studying the mechanism of YJP treating DHD.

Nature's soothing solution: Harnessing the potential of food-derived polysaccharides to control inflammation

Reducing inflammation by diet is a major goal for prevention or lowering symptoms of a variety of diseases, such as auto-immune reactions and cancers. Natural polysaccharides are increasingly gaining attention due to their potential immunomodulating capacity. Structures of those molecules are highly important for their effects on the innate immune system, cytokine production and secretion, and enzymes in immune cells. Such polysaccharides include β-glucans, pectins, fucoidans, and fructans. To better understand the potential of these immunomodulatory molecules, it is crucial to enhance dedicated research in the area. A bibliometric analysis was performed to set a starting observation point. Major pillars of inflammation, such as pattern recognition receptors (PRRs), enzymatic production of inflammatory molecules, and involvement in specific pathways such as Nuclear-factor kappa-B (NF-kB), involved in cell transcription, survival, and cytokine production, and mitogen-activated protein kinase (MAPK), a regulator of genetic expression, mitosis, and cell differentiation. Therefore, the outcomes from polysaccharide applications in those scenarios are discussed.

Characterizing the Pathogenicity and Immunogenicity of Simian Retrovirus Subtype 8 (SRV-8) Using SRV-8-Infected Cynomolgus Monkeys

Simian retrovirus subtype 8 (SRV-8) infections have been reported in cynomolgus monkeys (Macaca fascicularis) in China and America, but its pathogenicity and immunogenicity are rarely reported. In this work, the SRV-8-infected monkeys were identified from the monkeys with anemia, weight loss, and diarrhea. To clarify the impact of SRV-8 infection on cynomolgus monkeys, infected monkeys were divided into five groups according to disease progression. Hematoxylin (HE) staining and viral loads analysis showed that SRV-8 mainly persisted in the intestine and spleen, causing tissue damage. Additionally, the dynamic variations of blood routine indexes, innate and adaptive immunity, and the transcriptomic changes in peripheral blood cells were analyzed during SRV-8 infection. Compared to uninfected animals, red blood cells, hemoglobin, and white blood cells were reduced in SRV-8-infected monkeys. The percentage of immune cell populations was changed after SRV-8 infection. Furthermore, the number of hematopoietic stem cells decreased significantly during the early stages of SRV-8 infection, and returned to normal levels after antibody-mediated viral clearance. Finally, global transcriptomic analysis in PBMCs from SRV-8-infected monkeys revealed distinct gene expression profiles across different disease stages. In summary, SRV-8 infection can cause severe pathogenicity and immune disturbance in cynomolgus monkeys, and it might be responsible for fatal virus-associated immunosuppressive syndrome.

Serum amyloid A regulates TLR2/4-mediated IFN-β signaling pathway against Marek's disease virus

Serum amyloid A (SAA), an acute response phase protein (APP), is crucial for the innate immune response during pathogenic microorganisms' invasion. Marek's disease virus (MDV) is a highly oncogenic alphaherpesvirus that activates multiple innate immune molecules, including SAA, in the host during infection. However, the pathway through which SAA participates in MDV-induced host innate immunity remains unknown. The present study aimed to elucidate the pathway through which SAA exerts its anti-MDV function. We observed that MDV infection in vivo and in vitro significantly elevated SAA expression. Furthermore, through SAA overexpression and knockdown experiments, we demonstrated that SAA could inhibit MDV replication. Subsequently, we found that SAA activated Toll-Like Receptor 2/4 (TLR2/4) -mediated Interferon Beta (IFN-β) promoter activity and IFN regulatory factor 7 (IRF7) promoter activity. During MDV infection, SAA enhanced TLR2/4-mediated IFN-β signal transduction and messenger RNAs (mRNAs) expression of type I IFN (IFN-I) and interferon-stimulated genes (ISGs). Finally, TLR2/4 inhibitor OxPAPC inhibits the anti-MDV activity of SAA. These results demonstrated that SAA inhibits MDV replication and enhancing TLR2/4-mediated IFN-β signal transduction to promote IFNs and ISGs expression. This finding is the first to demonstrate the signaling pathway by which SAA exerts its anti-MDV function. It also provides new insights into the control of oncogenic herpesviruses from the perspective of acute response phase proteins.

Exploring the mechanism of the Fructus Mume and Rhizoma Coptidis herb pair intervention in Ulcerative Colitis from the perspective of inflammation and immunity based on systemic pharmacology

PURPOSE

Ulcerative Colitis (UC) is a chronic nonspecific inflammatory disease of the colon and rectum. Fructus Mume (FM) and Rhizoma Coptidis (RC) exert effects on inflammatory and immune diseases. We evaluated the hypothesis of the FM and RC (FM-RC) herb pair remedy in alleviating dextran sulfate sodium (DSS)-induced colitis, through network pharmacology-based analyses, molecular docking, and experimental validation.

METHODS

The Traditional Chinese medicine systematic pharmacology analysis platform(TCMSP) and Swiss database were used to predict potential targets of FM-RC and the GeneCards database was utilized to collect UC genes. Cytoscape software was used to construct and analyze the networks, and DAVID was utilized to perform enrichment analysis. AutoDock software was used to dock the core chemical components of the FM-RC herb pair with key UC targets. Animal experiments were performed to validate the prediction results and general conditions and body weight were observed. Pathological changes in colon tissue were observed by staining with hematoxylin and eosin. The levels of TNF-α, IL-8, IL-17, and IL-4 in serum and colon tissue were detected by ELISA.

RESULTS

Eighteen effective components of the herb couple were screened, and their potential therapeutic targets in the treatment of UC were acquired from 110 overlapped targets. GO and KEGG analyses revealed that these targets were highly correlated with protein autophosphorylation, plasma membrane, ATP binding, cancer pathways, the PI3K-AKt signaling pathway, and the Rap1 signaling pathway. Molecular docking established the core protein interactions with compounds having a docking energy < 0 kJ·mol^-1, indicating the core active components had strong binding activities with the core targets. FM-RC herb pair relieved pathological indicators and reduced the concentration of TNF-α, IL-8, and IL-17 and increased IL-4 levels in the serum and colon tissues of UC rats.

CONCLUSION

Collectively, FM-RC herb pair administration alleviated UC. These beneficial effects targeted MAPK1 signaling related to inflammation and immunity, which provided a basis for a better understanding of FM-RC in the treatment of UC.

Aeromonas hydrophila infection induces Toll-like receptor 2 (tlr2) and associated downstream signaling in Indian catfish, Clarias magur (Hamilton, 1822)

Motile Aeromonas septicaemia (MAS), caused by Aeromonas hydrophila, is one of the most significant bacterial disease responsible for mortality in Indian catfish, Clarias magur, a potential aquaculture species in the Indian subcontinent. In fish, innate immunity elicited by pathogen recognition receptors (PRRs) plays an important role in providing protection against bacterial infection. Information on PRRs including Toll-like receptors (tlrs) and their response to bacterial pathogens remains unexplored in magur. Toll-like receptor 2 (tlr2), a phylogenetically conserved germ-line encoded PRR recognizes specific microbial structure and trigger MyD88-dependent signaling pathway to induce release of various cytokines responsible for innate immune response. In the present study, tlr2 gene of magur was characterized and downstream signaling was studied following challenge with A. hydrophila. The full-length cDNA of magur tlr2 (mtlr2) comprised of 3,066 bp with a single open reading frame of 2,373 bp encoding 790 amino acids having a theoretical pI value of 6.11 and molecular weight of 90 kDa. Structurally, it comprised of signal peptide (1–42aa), one leucine-rich repeat region (LRR) at N-terminal (LRR1-NT: 50–73 aa) and C-terminal (LRR-CT: 588–608 aa), twenty LRRs in between, one trans-membrane (Tm) domain (609–631aa) followed by cytoplasmic TIR domain (670–783aa). Phylogenetically, mtlr2 is closely related to pangasius and channel catfish. Highest basal expression of mtlr2, myd88 and il-1β in spleen, nf-kb in anterior kidney was observed. Lowest basal expression of mtlr2 in skin and myd88, nf-kb and il-1β in muscle was detected. Significant up-regulation of mtlr2 and downstream expression occurred at 3, 8, 24 h post infection to A. hydrophila in important immune organs such as liver, spleen, intestine and kidney. These findings highlight the vital role of tlr2 in eliciting innate immune defence against A. hydrophila infection.

Severe Acute Respiratory Syndrome Coronavirus-2 Spike Protein Nanogel as a Pro-Antigen Strategy with Enhanced Protective Immune Responses

Prevention and intervention methods are urgently needed to curb the global pandemic of coronavirus disease-19 caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Herein, a general pro-antigen strategy for subunit vaccine development based on the reversibly formulated receptor binding domain of SARS-CoV-2 spike protein (S-RBD) is reported. Since the poor lymph node targeting and uptake of S-RBD by antigen-presenting cells prevent effective immune responses, S-RBD protein is formulated into a reversible nanogel (S-RBD-NG), which serves as a pro-antigen with enhanced lymph node targeting and dendritic cell and macrophage accumulation. Synchronized release of S-RBD monomers from the internalized S-RBD-NG pro-antigen triggers more potent immune responses in vivo. In addition, by optimizing the adjuvant used, the potency of S-RBD-NG is further improved, which may provide a generally applicable, safer, and more effective strategy for subunit vaccine development against SARS-CoV-2 as well as other viruses.

Inhibition of nuclear factor kappa B as a mechanism of Danshensu during Toll-like receptor 2-triggered inflammation in macrophages

Danshensu (DSS) is a water-soluble phenolic compound in Danshen (Salvia Miltiorrhiza Radix et Rhizoma). Although various pharmacological activities have been recognized, little is known regarding its anti-inflammatory effect and related molecular mode of action. In the current study, bone marrow-derived macrophages (BMMs) were activated by a Toll-like receptor 2 (TLR2) agonist Pam3CSK4 with or without DSS intervention. Production of pro-inflammatory cytokines interleukin-6 (IL-6) and interleukin-12 (IL-12) was detected by both enzyme-linked immunosorbent assay (ELISA) and real-time quantitative PCR (RT-qPCR). Activation of signaling pathways involving nuclear factor kappa B (NF-κB) and mitogen-activated protein kinases (MAPKs) was assessed by Western blot. Additionally, RNA sequencing (RNA-seq) combined with bioinformatics analyses was applied to investigate the molecular mechanisms of DSS. Emphasis was placed on the construction of the protein-protein interaction (PPI) network and transcription factor (TF) enrichment analysis of data including co-regulated differentially expressed genes (DEGs) in the Pam3CSK4 vs. control and DSS vs. Pam3CSK4 groups. The RT-qPCR and ELISA results showed that DSS effectively inhibited the expressions of IL-6 and IL-12, indicating a significant anti-inflammatory effect. Western blot verified that DSS suppressed the phosphorylation of p65, which was in accordance with the results of the TF enrichment analysis. Additionally, the PPI network analysis showed several key molecules, including lactoferrin (Ltf), CC-chemokine receptor 7 (Ccr7), interferon-gamma (IFN-γ) and C-X-C motif chemokine ligand 9 (Cxcl9), to be regulatory genes that responded to DSS treatment. Overall, our study revealed that DSS has a pronounced anti-inflammatory effect involving TLR2 and macrophages through the NF-κB signaling pathway, which supports the novel application of DSS in the treatment of relevant diseases including atherosclerosis and ischemic or ischemic/perfusion injury of the heart and brain.

Neutrophils as a Protagonist and Target in Chronic Rhinosinusitis

Neutrophils have traditionally been acknowledged as the first immune cells that are recruited to inflamed tissues during acute inflammation. By contrast, their importance in the context of chronic inflammation has been studied in less depth. Neutrophils can be recruited and are largely present in the nasal mucosa of patients with chronic rhinosinusitis (CRS) both in Asians and in Caucasians. Increased infiltration of neutrophils in patients with CRS has been linked to poor corticosteroid response and disease prognosis. Meanwhile, tissue neutrophils may possess specific phenotypic features distinguishing them from resting blood counterparts and are endowed with particular functions, such as cytokines and chemokines production, thus may contribute to the pathogenesis of CRS. This review aims to summarize our current understanding of the pathophysiologic mechanisms of CRS, with a focus on the roles of neutrophils. We discuss recruitment, function, and regulation of neutrophils in CRS and outline the potential therapeutic strategies targeting neutrophils.