Toll-like receptors

Regulatory effect of curcumin on CD40:CD40L interaction and therapeutic implications

Natural compounds have garnered significant attention as potential therapeutic agents due to their inherent properties. Their notable qualities, including safety, efficacy, favorable pharmacokinetic properties, and heightened effectiveness against certain diseases, particularly inflammatory conditions, make them particularly appealing. Among these compounds, curcumin has attracted considerable interest for its unique therapeutic properties and has therefore been extensively studied as a potential therapeutic agent for treating various diseases. Curcumin exhibits diverse anti-inflammatory, antioxidant, and antimicrobial effects. Curcumin's immune system regulatory ability has made it a promising compound for treatment of various inflammatory diseases, such as psoriasis, atherosclerosis, asthma, colitis, IBD, and arthritis. Among the signaling pathways implicated in these conditions, the CD40 receptor together with its ligand, CD40L, are recognized as central players. Studies have demonstrated that the interaction between CD40 and CD40L interaction acts as the primary mediator of the immune response in inflammatory diseases. Numerous studies have explored the impact of curcumin on the CD40:CD40L pathway, highlighting its regulatory effects on this inflammatory pathway and its potential therapeutic use in related inflammatory conditions. In this review, we will consider the evidence concerning curcumin's modulatory effects in inflammatory disease and its potential therapeutic role in regulating the CD40:CD40L pathway.

Toll-Like Receptor 4 (TLR4) Promotes DRG Regeneration and Repair after Sciatic Nerve Injury via the ERK-NF-kB Pathway

Previously, we found that the expression of Toll-like receptor 4 (TLR4) is altered after sciatic nerve injury, and its differential expression plays a key role in recovery. However, the mechanisms by which TLR4 affects neuronal function in the dorsal root ganglion (DRG) have not been completely evaluated. The objective is to determine TLR4 expression in DRG tissues after sciatic neural injury and exploring the effects of TLR4 knockdown and overexpression in the DRG on neuronal function and nerve regeneration in rats in vivo and in vitro. We established a model of nerve injury and utilized molecular biology and cell biology experiments to explore the molecular mechanisms by which TLR4 in the DRG affects sciatic nerve restoration and regeneration after injury. Verified the localization of TLR4 in DRG neurons. Investigated pathways that related to apoptosis or nerve regeneration by which TLR4 regulates the function of DRG neurons. TLR4 expression was upregulated in the DRG tissues of rats after sciatic nerve injury. TLR4 overexpression promoted axon regeneration and inhibited apoptosis in DRG neurons. TLR4 promoted the regeneration of axons and the recovery of motor and sensory functions in the sciatic nerve after injury in vivo, and the data showed that TLR4 may regulate the function of DRG neurons and promote nerve repair and regeneration through the ERK and NF-κB signaling pathways in vivo and ex vivo. The study suggests that TLR4 may regulate the function of DRG neurons and promote nerve regeneration by affecting the ERK and NF-κB signaling pathways.

Recognition Mechanism of RNA by TLR13: Structural Insights and Implications for Immune Activation

RNA serves as a distinctive pathogen-associated molecular pattern (PAMP) that plays a critical role in innate immunity. However, the specific mechanisms of RNA recognition remain largely unexplored, especially given RNA's vulnerability to degradation and the absence of sequence specificity in most RNA recognition receptors. Notably, Toll-like receptor 13 (TLR13) is capable of detecting a conserved RNA sequence, RNA15 (2054-2068, ACG GAA AGA CCC CGU), within bacterial 23S rRNA, thereby triggering an immune response. To unravel the exact mechanism by which TLR13 recognizes RNA15, we combined experimental approaches with molecular dynamics simulations. Our results suggest that RNA15 adopts a stable hairpin structure in solution, protected from nuclease degradation by intramolecular interactions. TLR13 specifically recognizes this hairpin structure, leading to the dimerization of TLR13. This interaction further induces RNA15 to transition into a stem-loop-like conformation, thereby activating TLR13 downstream signaling. Additionally, our study indicates that TLR13 can form stable dimers in the membrane independently of ligand binding. Although the hairpin structure is the predominant form of RNA15 in solution, the temporary stem-loop-like structure can spontaneously bind to dimeric TLR13, initiating the immune response. These insights deepen our understanding of the complex recognition process of RNA15 by TLR13 and explore the complicated mechanisms governing innate immune system function.

Regulation of osteoclast-mediated bone resorption by lipids

Hyperactivation of osteoclasts has been identified as a significant etiological factor in several bone resorption-related disorders, including osteoporosis, periodontitis, arthritis, and bone metastasis of tumors. It has been demonstrated that the severity of these diseases is influenced by lipids that regulate osteoclast differentiation and activity through specific signaling pathways and cytokine levels. The regulatory mechanisms of different types of lipids on osteoclastogenesis vary across diverse disease contexts in bone resorption regulated by osteoclasts. This review presents an overview of the mechanisms underlying osteoclast formation and summarizes the pathways through which various lipids regulate osteoclastogenesis in different pathological contexts. We also discuss effective therapeutic strategies for osteolytic diseases based on modulation of lipid metabolism.

Investigating the impact of mitochondrial DNA: Insights into blood transfusion reactions and mitigation strategies

BACKGROUND AND OBJECTIVES

Although transfusion reactions occur in less than 2% of recipients, they are currently one of the most serious concerns in blood transfusion. Damage-associated molecular patterns (DAMPs) are released from injured, stressed or dead cells, leading to inflammation and immune system activation. One of the recognized DAMPs is mitochondrial DNA (mtDNA). It is found in various blood products, including fresh frozen plasma (FFP), red blood cell units (RBCUs) and platelet concentrates (PCs), and can induce adverse reactions in recipients by stimulating the innate immune system and inflammatory cellular pathways. The aim of this study was to investigate the factors influencing the release of mtDNA in various blood products and its subsequent impact on transfusion reactions.

MATERIALS AND METHODS

In this study, mtDNA, mitochondrial DNA, mtDNA DAMPs, extracellular mtDNA, blood products, blood components and transfusion reactions between 2009 and 2023 were searched in Google Scholar, PubMed and Scopus databases.

RESULTS

This study has demonstrated the presence of mtDNA in the extracellular milieu of various blood products, including PCs, FFP and RBCUs. Understanding the determinants of mtDNA release and its implications for transfusion safety is critical. Strategies aimed at reducing mtDNA release, such as optimizing preparation techniques and donor selection criteria, hold promise for reducing transfusion-related complications.

CONCLUSION

By addressing these factors, healthcare providers can enhance the safety and efficacy of blood transfusion practices, ultimately improving patient outcomes.

Bidirectional Communication Between the Innate and Adaptive Immune Systems

Effective bidirectional communication between the innate and adaptive immune systems is crucial for tissue homeostasis and protective immunity against infections. The innate immune system is responsible for the early sensing of and initial response to threats, including microbial ligands, toxins, and tissue damage. Pathogen-related information, detected primarily by the innate immune system via dendritic cells, is relayed to adaptive immune cells, leading to the priming and differentiation of naive T cells into effector and memory lineages. Memory T cells that persist long after pathogen clearance are integral for durable protective immunity. In addition to rapidly responding to reinfections, memory T cells also directly instruct the interacting myeloid cells to induce innate inflammation, which resembles microbial inflammation. As such, memory T cells act as newly emerging activators of the innate immune system and function independently of direct microbial recognition. While T cell-mediated activation of the innate immune system likely evolved as a protective mechanism to combat reinfections by virulent pathogens, the detrimental outcomes of this mechanism manifest in the forms of autoimmunity and other T cell-driven pathologies. Here, we review the complexities and layers of regulation at the interface between the innate and adaptive immune systems to highlight the implications of adaptive instruction of innate immunity in health and disease.

Nucleic acid triggers of autoimmunity and autoinflammation

The key role of nucleic acid sensing receptors in the development of autoimmune and autoinflammatory diseases is becoming increasingly apparent. Activation of these sensors has been attributed to the failure of professional scavenger cells to adequately clear cell debris, in many cases due to defective scavenger receptors. However, as now summarized in this review, numerous gain-of-function mutations in the nucleic acid sensing receptors, or in molecules that regulate sensor activity, have now been evaluated in gene-targeted murine strains, and critical components of their downstream pathways have been identified as therapeutic targets. In addition, we are beginning to understand how DNases and RNases play crucial roles in both generating and eliminating the distinct ligands that engage the various nucleic acid sensors. Murine models of disease have further provided important insights regarding the function of and synergy between individual endosomal and cytosolic receptors, as well as cell type restricted functions.

A plant virus attenuates the Toll immune pathway by degradation of Pellino to facilitate viral infection in insect vectors

Many plant viruses are persistently transmitted by insect vectors. The viral antagonism of insect innate immune responses is a critical step in ensuring persistent viral infection. Recent studies have shown that the Toll immune pathway mediates the persistent and propagative transmission of rice stripe virus (RSV) in its insect vector (Laodelphax striatellus). However, whether other host factors are involved in the Toll pathway and how RSV counteracts the Toll immune response in L. striatellus remain unclear. Here, we reported that LsPellino also inhibited RSV infection in L. striatellus by interacting with LsTube and participating in the Toll immune pathway. In contrast, the viral nonstructural protein NS3 hijacked the suppressor of cytokine signaling 5 (LsSOCS5) to promote the degradation of LsPellino via the 26S proteasome pathway, thereby suppressing the Toll immune response. In summary, these findings demonstrate that RSV attenuates the Toll immune pathway by degradation of LsPellino to facilitate viral infection in insect vectors. Our research provides new insights into controlling the transmission of vector-borne viruses.

IMPORTANCE

Plant virus diseases pose a serious threat to global crop production. Nearly half of the known plant viruses are persistently transmitted by insect vectors, and these plant viruses must counteract various innate immune responses to maintain persistent infection. Here, we uncover a novel counter-defense mechanism against Toll antiviral defense. Our research showed that LsPellino exerts antiviral function by interacting with LsTube and participating in the Toll immune pathway. To counteract this immunity, a plant virus, rice stripe virus, attenuates the Toll immune pathway and promotes viral infection by using viral nonstructural protein NS3 to mediate the degradation of LsPellino in its insect vector, Laodelphax striatellus. This study not only contributes to a better understanding of the arms race between viruses and insect vectors but also provides a new perspective for controlling the transmission of plant viruses.

Elucidating the immunomodulatory roles and mechanisms of CUL4B in the immune system: a comprehensive review

Cullin 4B (CUL4B), a pivotal member of the Cullins protein family, plays a crucial role in immune regulation and has garnered significant research attention. CUL4B, through the Cullin 4B-RING E3 ubiquitin ligase (CRL4B) complex, regulates CD4+ T cell differentiation, fostering a balance between TH1 and TH2 subsets, and expedites DNA damage repair to bolster T cell persistence. In B cells, CUL4B upregulation stimulates immune responses but is linked to an unfavorable prognosis in lymphoma. In innate immunity, CUL4B modulates Toll-like receptor (TLR)-mediated anti-inflammatory responses, enhancing macrophage migration and adhesion. CUL4B also plays a role in potentiating anti-tumor immunity by restricting the activity of myeloid-derived suppressor cells (MDSCs). In disease pathogenesis, CUL4B limits MDSCs to enhance anti-tumor effects, and its inhibition in experimental autoimmune encephalomyelitis (EAE) models have demonstrated beneficial effects, underscoring its potential therapeutic significance in autoimmune diseases. Furthermore, CUL4B is involved in various immune-related cancers and inflammation, including pleural mesothelioma, human osteosarcoma, and colitis-associated cancer. In metabolic diseases, CUL4B regulates adipose tissue and insulin sensitivity, with its depletion improving metabolic phenotypes. This review highlights the pivotal role of CUL4B in maintaining immune homeostasis and provides novel perspectives and insights into the understanding and development of treatments for immune-related disorders.

BBB breakdown caused by plasma membrane pore formation

The blood-brain barrier, recently reintroduced as the blood-brain border (BBB), is a dynamic interface between the central nervous system (CNS) and the bloodstream. Disruption of the BBB exposes the CNS to peripheral pathogens and harmful substances, causing or worsening various CNS diseases. While traditional views attribute BBB failure to tight junction disruption or increased transcytosis, recent studies highlight the critical role of gasdermin D (GSDMD) pore formation in brain endothelial cells (bECs) during BBB disruption by lipopolysaccharide (LPS) or bacterial infections. This mechanism may also be involved in neurological complications like the 'brain fog' seen in long COVID. Pore formation in bECs may represent a prevalent mechanism causing BBB leakage. Investigating membrane-permeabilizing pores or channels and their effects on BBB integrity is a growing area of research. Further exploration of molecular processes that maintain, disrupt, and restore bEC membrane integrity will advance our understanding of brain vasculature and aid in developing new therapies for BBB-related diseases.

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.

In Vivo Evidence on the Emerging Potential of Non-Digestible Oligosaccharides as Therapeutic Agents in Bacterial and Viral Infections

The issue of antibiotic-resistant bacterial infections, coupled with the rise in viral pandemics and the slow development of new antibacterial and antiviral treatments, underscores the critical need for novel strategies to mitigate the spread of drug-resistant pathogens, enhance the efficacy of existing therapies, and accelerate the discovery and deployment of innovative antimicrobial and antiviral solutions. One promising approach to address these challenges is the dietary supplementation of non-digestible oligosaccharides (NDOs). NDOs, including human milk oligosaccharides (HMOs), play a vital role in shaping and sustaining a healthy gut microbiota. Beyond stimulating the growth and activity of beneficial gut bacteria, NDOs can also interact directly with pathogenic bacteria and viruses. Their antiviral and antibacterial properties arise from their unique interactions with pathogens and their ability to modulate the host's immune system. NDOs can function as decoy receptors, inhibit pathogen growth, bind to bacterial toxins, stimulate the host immune response, exhibit anti-biofilm properties, and enhance barrier protection. However, a notable gap exists in the comprehensive assessment of in vivo and clinical data on this topic. This review aims to provide an in-depth overview of the in vivo evidence related to the antiviral and antibacterial effects of various NDOs and HMOs, with a focus on discussing their possible mechanisms of action.

Cytosolic nucleic acid sensing as driver of critical illness: mechanisms and advances in therapy

Nucleic acids from both self- and non-self-sources act as vital danger signals that trigger immune responses. Critical illnesses such as acute respiratory distress syndrome, sepsis, trauma and ischemia lead to the aberrant cytosolic accumulation and massive release of nucleic acids that are detected by antiviral innate immune receptors in the endosome or cytosol. Activation of receptors for deoxyribonucleic acids and ribonucleic acids triggers inflammation, a major contributor to morbidity and mortality in critically ill patients. In the past decade, there has been growing recognition of the therapeutic potential of targeting nucleic acid sensing in critical care. This review summarizes current knowledge of nucleic acid sensing in acute respiratory distress syndrome, sepsis, trauma and ischemia. Given the extensive research on nucleic acid sensing in common pathological conditions like cancer, autoimmune disorders, metabolic disorders and aging, we provide a comprehensive summary of nucleic acid sensing beyond critical illness to offer insights that may inform its role in critical conditions. Additionally, we discuss potential therapeutic strategies that specifically target nucleic acid sensing. By examining nucleic acid sources, sensor activation and function, as well as the impact of regulating these pathways across various acute diseases, we highlight the driving role of nucleic acid sensing in critical illness.

Targeted Delivery of TLR7 Agonists to the Tumor Microenvironment Enhances Tumor Immunity via Activation of Tumor-Resident Myeloid Cells

Toll-like receptors (TLR) are phylogenetically conserved mediators of innate immunity that are essential for establishing adaptive immune responses against invading pathogens. TLR7 is an endosomal receptor expressed predominantly in myeloid and B cells. Activation of TLR7 induces Type I interferon and proinflammatory responses; therefore, targeting TLR7 is a promising strategy for antitumor therapy. Although the use of bacterial components to trigger innate immune responses in cancer patients started a century ago, the effectiveness of systemic TLR agonists has been rather underwhelming in clinical trials, partly due to nonspecific immune activation leading to safety and tolerability issues. Antibody-drug conjugates (ADCs) constitute a proven therapeutic modality amenable to systemic administration with limited toxicity concerns via a targeted delivery platform. We generated TLR7 agonist-antibody conjugates that recognize tumor antigens expressed on the surface of tumor cells. Generated ADCs demonstrated robust activity in in vitro tumor antigen-presenting cell (APC) coculture systems as indicated by dose-dependent upregulation of PD-L1 and CD86 on macrophages. TLR7 agonist-ADC provided superior tumor growth control compared to intravenously (IV) administrated free TLR7 agonist. Treatment with TLR7 agonist-ADC led to prolonged activation of myeloid cells in the tumor microenvironment (TME) with minimum immune activation in the periphery. Systemic and tissue exposure studies demonstrated tumor-specific free drug release by targeted ADC treatment. In summary, the TLR7 agonist-ADC can potentially activate immune cells in the TME to generate tumor antigen-specific T-cell responses, making it an attractive approach for precision cancer therapy.

Toll Like Receptors Promote High Glucose-Induced Vascular Endothelial Cell Dysfunction by Regulating Neutrophil Extracellular Traps Formation

Diabetic retinopathy (DR) is a major cause of blindness globally. Neutrophils and neutrophil extracellular traps (NETs) are believed to play a role in the development of DR. However, the specific contribution of NETs to hyperglycemia-induced vascular endothelial cell dysfunction remains unclear. In this study, we cocultured high glucose-activated neutrophils (HGNs) with human umbilical vein endothelial cells (HUVECs) to investigate the role of NETs in high glucose-induced HUVEC dysfunction. Our findings indicate that high glucose levels promote NETs formation, which can be inhibited by a toll-like receptor (TLR) 2 antagonist and a TLR4 antagonist. It was observed that reactive oxygen species production plays a role in TLR2- but not TLR4-mediated NETs formation. Additionally, HGNs were found to promote HUVEC proliferation through phagocytosis rather than NETs. We also discovered that NETs contribute to high glucose-induced HUVEC dysfunction by enhancing neutrophil-HUVEC adhesion, inhibiting HUVEC migration, and compromising the barrier function of the cells by reducing zonula occludens-1 expression. This dysfunction could be partially mitigated by TLR2 and TLR4 antagonists. In conclusion, high glucose stimulates NETs formation, leading to vascular endothelial cell damage, and TLRs may facilitate high glucose-induced endothelial dysfunction by modulating NETs formation.

Resveratrol Upregulates Antioxidant Factors Expression and Downmodulates Interferon-Inducible Antiviral Factors in Aging

Immunosenescence, a process with a dysfunctional immune response that may favor infection is associated with an increase in inflammatory responses mediated by proinflammatory cytokines, characteristic of inflammaging. Aging and immunosenescence have a relationship relating to oxidative stress and inflammaging. Therefore, natural antioxidant compounds could be candidates for the control of the oxidative process. Our purpose was to evaluate the effect of resveratrol (Resv) on the antioxidant, antiviral, and anti-inflammatory responses induced by toll-like receptors (TLRs) 3, 4, and 7/8 agonists stimulation on peripheral blood mononuclear cells (PBMCs) of elderly and healthy female individuals (63-82 years old) and young and healthy female individuals (21-31 years old). Our data show that Resv may upregulate antioxidant factor expression, such as catalase (CAT) and SIRT1, in response to TLR4 and TLR7/8 agonists, similarly in both young and aged groups. Moreover, the Resv anti-inflammatory effect was detected by inhibiting IL-1β, TNF-α, and IL-10 secretion levels, as well as by the chemokines CCL2 and CCL5, induced by TLR4 and TLR7/8 stimulation. Curiously, Resv decreased antiviral genes, such as MxA, STING, and IRF7 expression, possibly by reducing the inflammatory effects of interferon-induced genes. Taken together, our results demonstrate the ability of Resv to stimulate antioxidant factors, leading to a downmodulation of the inflammatory response induced by innate immune stimulation. These findings point out Resv as a strategy to control the upregulation of inflammatory response, even in elderly individuals.

BT1549 coordinates the in vitro IL-10 inducing activity of Bacteroides thetaiotaomicron

The intestine is home to a complex immune system that is engaged in mutualistic interactions with the microbiome that maintain intestinal homeostasis. A variety of immune-derived anti-inflammatory mediators have been uncovered and shown to be critical for maintaining these beneficial immune-microbiome relationships. Notably, the gut microbiome actively invokes the induction of anti-inflammatory pathways that limit the development of microbiome-targeted inflammatory immune responses. Despite the importance of this microbiome-driven immunomodulation, detailed knowledge of the microbial factors that promote these responses remains limited. We have previously established that the gut symbiont Bacteroides thetaiotaomicron stimulates the production of the anti-inflammatory cytokine IL-10 via soluble factors in a Toll-like receptor 2 (TLR2)-MyD88-dependent manner. Here, using TLR2 activity reporter cell lines, we show that the capacity of B. thetaiotaomicron to stimulate TLR2 activity was not critically dependent on either of the canonical heterodimeric forms of TLR2, TLR2/TLR1, or TLR2/TLR6, that typically mediate its function. Furthermore, biochemical manipulation of B. thetaiotaomicron-conditioned media suggests that IL-10 induction is mediated by a protease-resistant or non-proteogenic factor. We next uncovered that deletion of gene BT1549, a predicted secreted lipoprotein, significantly impaired the capacity of B. thetaiotaomicron to induce IL-10, while complementation in trans restored IL-10 induction, suggesting a role for BT1549 in the immunomodulatory function of B. thetaiotaomicron. Collectively, these data provide molecular insight into the pathways through which B. thetaiotaomicron operates to promote intestinal immune tolerance and symbiosis.

IMPORTANCE

Intestinal homeostasis requires the establishment of peaceful interactions between the gut microbiome and the intestinal immune system. Members of the gut microbiome, like the symbiont Bacteroides thetaiotaomicron, actively induce anti-inflammatory immune responses to maintain mutualistic relationships with the host. Despite the importance of such interactions, the specific microbial factors responsible remain largely unknown. Here, we show that B. thetaiotaomicron, which stimulates Toll-like receptor 2 (TLR2) to drive IL-10 production, can stimulate TLR2 independently of TLR1 or TLR6, the two known TLR that can form heterodimers with TLR2 to mediate TLR2-dependent responses. Furthermore, we show that IL-10 induction is likely mediated by a protease-resistant or non-proteogenic factor, and that this requires gene BT1549, a predicted secreted lipoprotein and peptidase. Collectively, our work provides insight into the molecular dialog through which B. thetaiotaomicron coordinates anti-inflammatory immune responses. This knowledge may facilitate future strategies to promote such responses for therapeutic purposes.

The Role of TLRs in Obesity and Its Related Metabolic Disorders

Obesity affects the adaptability of adipose tissue (AT), impairing its ability to regulate energy and metabolism. Obesity is associated with many metabolic disorders, including dyslipidemia, hypertension, sleep disorders, non-alcoholic liver disease, and some types of cancer. Toll-like receptors (TLRs) are important in obesity and related metabolic disorders. TLRs are pattern-recognizing receptors (PRRs) involved in the innate immune system and recognize pathogen-associated molecular patterns (PAMPs) and endogenous ligands. TLRs, especially TLR2 and TLR4, are activated by fatty acids, endotoxins, and other ligands. TLR2 and TLR4 activation triggers inflammatory responses. Chronic inflammation driven by TLR activation is a hallmark of obesity and metabolic diseases. The inflammatory response triggered by TLR activation alters insulin signaling, contributing to insulin resistance, a key feature of metabolic syndrome and type 2 diabetes. Modulation of TLR activity through lifestyle changes (diet and exercise), obesity surgery, and pharmacological agents is under study as a possible therapeutic approach to controlling obesity and its complications.

Innate Immunity in Helicobacter pylori Infection and Gastric Oncogenesis

Helicobacter pylori is an extremely common cause of gastritis that can lead to gastric adenocarcinoma over time. Approximately half of the world's population is infected with H. pylori, making gastric cancer the fourth leading cause of cancer-related deaths worldwide. Innate immunity significantly contributes to systemic and local immune responses, maintains homeostasis, and serves as the vital link to adaptive immunity, and in doing so, mediates H. pylori infection outcomes and consequent cancer risk and development. The gastric innate immune system, composed of gastric epithelial and myeloid cells, is uniquely challenged by its need to interact simultaneously and precisely with commensal microbiota, exogenous pathogens, ingested substances, and endogenous exfoliated cells. Additionally, innate immunity can be detrimental by promoting chronic infection and fibrosis, creating an environment conducive to tumor development. This review summarizes and discusses the complex role of innate immunity in H. pylori infection and subsequent gastric oncogenesis, and in doing so, provides insights into how these pathways can be exploited to improve prevention and treatment.

Transcriptomic and biometric parameters analysis in rainbow trout (Oncorhynchus mykiss) challenged with viral hemorrhagic septicemia virus (VHSV)

BACKGROUND

Viral hemorrhagic septicemia virus (VHSV) is a highly pathogenic virus that poses a significant threat to the health of diverse marine species. Among these, trout species, particularly rainbow trout (Oncorhynchus mykiss), are highly susceptible. This study evaluated the effects of VHSV infection on the biometric traits of rainbow trout and investigated the molecular mechanisms associated with the disease.

RESULTS

Biometric traits of fish were collected and documented weekly during the fourth and fifth weeks of the experiment. A statistically significant difference in body weight was observed in the fifth week, particularly between the control group and the groups injected with either physiological saline or the virus. Additionally, body length-related attributes showed significant variation across all treatment groups within the designated timeframe. RNA was extracted from spleen tissue of the group injected with high doses of physiological saline and the group injected with high doses of the virus using the TRIzol protocol. Differential gene expression analysis revealed 1,726 genes with significant differences between the two groups. Several key immune-related genes were identified, including TLR2, TLR7, TLR8, TLR22, IRF5, IRF6, IRF7, IRF8, IRF10, IL11a, IL12B, IL1b, IL7R, ILR1 II, HSP90B1, HSP47, TNF-α, TRF3, SPRY1, CASP3, FN1, GAPDH, and IgGFc-binding proteins. Network-based analysis of differentially expressed genes was conducted using the GeneMANIA module in Cytoscape, and metabolic pathways were identified through the DAVID database. The results highlighted the involvement of key pathways, including the Toll-like receptor pathway, p53 signaling pathway, PPAR signaling pathway, and the cell cycle, in the infected group. Validation tests for selected upregulated (EPCAM, APOC2 and XDD4) and downregulated (TLR7, XDH, and TSPAN36) candidate genes, were conducted using qRT-PCR. The qPCR results showed a strong and statistically significant correlation with the RNA-seq data, confirming the reliability of the findings.

CONCLUSIONS

VHSV significantly impacts the growth of rainbow trout, affecting both body length and gene expression. This study underscores the substantial economic risks posed by the virus and the absence of an effective cure, highlighting the importance of preventative measures. Additionally, potential resistance genes and pathways were identified through RNA sequencing, providing valuable insights for improving trout breeding programs.

Sinensetin attenuates LPS-induced acute pulmonary inflammation in mice and RAW264.7 cells by modulating NF-κB p65-mediated immune resistance and STAT3-mediated tissue resilience

Acute pulmonary inflammation is a severe lower respiratory tract infection. Sinensetin (SIN), a polymethoxyflavone with strong anti-inflammatory properties, is known to ameliorate LPS-induced acute inflammatory lung injury, but its molecular mechanisms are not fully understood. This study aimed to provide insight into the pharmacological mechanisms of SIN in attenuating acute pulmonary inflammation. In LPS-induced inflammation assays in vivo and in vitro, SIN significantly reduced the mRNA levels of inflammatory genes including MCP-1, ICAM1, Ccl3, Ccl4, Ccl5, Ccl7, Cxcl9, Cxcl10, IL1α, IL1β, IL6, IL11, IL18, IL27, TNF-α, IFN-γ, TLR4, MyD88, F4/80, COX2, iNOS, NLRP3, ASC, JAK2, STAT3, STAT4, and Bcl2l1, as well as increased the mRNA levels of anti-inflammatory genes such as IL4, IL10, and IL12α. Besides, SIN markedly decreased the expression of CD68, TLR4, MyD88, phospho-IκBα (S32/S36), phospho-NF-κB p65 (S536), MCP-1, ICAM1, phospho-JAK2 (Tyr1008), phospho-STAT1 (S727), phospho-STAT3 (Y705), and phospho-STAT4 (Y693), inhibited NF-κB p65 translocation into the nucleus, thereby blocking in combination with STAT transcription factors to induce target gene expression. Further GC-MS/MS and LC-MS/MS metabolomic analysis revealed that SIN significantly increased the abundance of anti-inflammatory metabolites, such as L-alanine, L-carnitine, L-glutamic acid, Glycine, and L-cysteine. In conclusion, the results indicated that SIN attenuated LPS-induced acute pulmonary inflammation by modulating NF-κB p65-mediated immune resistance and STAT3-mediated tissue resilience. All these favorable findings presented critical insights into the remarkable abilities and health benefits of SIN in ameliorating inflammatory lung disease.

Pseudomonas aeruginosa-derived DnaJ induces TLR2 expression through TLR10-mediated activation of the PI3K-SGK1 pathway in macrophages

TLR2 is a key component of the innate immune system, responsible for recognizing Gram-positive bacterial components and initiating inflammatory signaling cascades that activate defense responses. However, little is known about the regulatory effects of Pseudomonas aeruginosa (P. aeruginosa) on TLR2 expression. In this study, we investigated the potential link between P. aeruginosa-derived DnaJ and TLR2 expression in macrophages, as well as the activation of downstream signaling pathways. Our findings revealed that DnaJ significantly induced TLR2 expression in a dose- and time-dependent manner, predominantly affecting TLR2 with minimal impact on other TLRs, such as TLR4 and TLR5, which detect bacterial PAMPs. The DnaJ-mediated TLR2 induction was driven by activation of the PI3K-SGK1 signaling pathway, with TLR10 playing a crucial role in facilitating these effects. This increase in TLR2 expression led to enhanced production of inflammatory cytokines in response to secondary Staphylococcus aureus infections, indicating a role in boosting host defense mechanisms. In conclusion, these findings suggest that P. aeruginosa-derived DnaJ promotes TLR2 expression via TLR10-mediated activation of the PI3K-SGK1 pathway, thereby enhancing host immune responses against Gram-positive bacterial infections.

Transcriptomic analysis of human cartilage identified potential therapeutic targets for hip osteoarthritis

Cartilage degradation is the hallmark of osteoarthritis (OA). The purpose of this study was to identify and validate differentially expressed genes (DEGs) in human articular cartilage that could serve as potential therapeutic targets for hip OA. We performed transcriptomic profiling in a discovery cohort (12 OA-free and 72 hip OA-affected cartilage) and identified 179 DEGs between OA-free and OA-affected cartilage after correcting for multiple testing (P < 2.97 × 10-6). Pathway and network analyses found eight hub genes to be associated with hip OA (ASPN, COL1A2, MXRA5, P3H1, PCOLCE, SDC1, SPARC, and TLR2), which were all confirmed using qPCR in a validation cohort (36 OA-free and 62 hip OA-affected cartilage) (P < 6.25 × 10-3). Our data showed that dysregulation of extracellular matrix formation and imbalance in the proportion of collagen chains may contribute to the development of hip OA, and SDC1 could be a promising potential therapeutic target. These findings provided a better understanding of the molecular mechanisms for hip OA and may assist in developing targeted treatment strategies.

The Chromosome-level Genome of the Ctenophore Mnemiopsis leidyi A. Agassiz, 1865 Reveals a Unique Immune Gene Repertoire

Ctenophora are basal marine metazoans, the sister group of all other animals. Mnemiopsis leidyi is one of the most successful invasive species worldwide with intense ecological and evolutionary research interest. Here, we generated a chromosome-level genome assembly of M. leidyi with a focus on its immune gene repertoire. The genome was 247.97 Mb, with N50 16.84 Mb, and 84.7% completeness. Its karyotype was 13 chromosomes. In this genome and that of two other ctenophores, Bolinopsis microptera and Hormiphora californensis, we detected a high number of protein domains related to potential immune receptors. Among those, proteins containing Toll/interleukin-1 (TIR2) domain, NACHT domain, Scavenger Receptor Cystein-Rich (SRCR) domain, or C-type Lectin domain (CTLD) were abundant and presented unique domain architectures in M. leidyi. M. leidyi seems to lack bona fide Toll-like Receptors, but it does possess a repertoire of 15 TIR2 domain-containing genes. Besides, we detected a bona fide NOD-like receptor and 38 NACHT domain-containing genes. In order to verify the function of those domain-containing genes, we exposed M. leidyi to the pathogen Vibrio coralliilyticus. Among the differentially expressed genes, we identified potential immune receptors, including four TIR2 domain-containing genes, all of which were upregulated in response to pathogen exposure. To conclude, many common immune receptor domains, highly conserved across metazoans, are already present in Ctenophora. These domains have large expansions and unique architectures in M. leidyi, findings consistent with the basal evolutionary position of this group, but still might have conserved functions in immunity and host-microbe interaction.

Systematic analysis of innate immune-related genes in the silkworm: Application to antiviral research

The silkworm, a crucial model organism of the Lepidoptera, offers an excellent platform for investigating the molecular mechanisms underlying the innate immune response of insects toward pathogens. Over the years, researchers worldwide have identified numerous immune-related genes in silkworms. However, these identified silkworm immune genes are not well classified and not well known to the scientific community. With the availability of the latest genome data of silkworms and the extensive research on silkworm immunity, it has become imperative to systematically categorize the immune genes of silkworms with different database IDs. In this study, we present a meticulous organization of prevalent immune-related genes in the domestic silkworm, using the SilkDB 3.0 database as a reliable source for updated gene information. Furthermore, utilizing the available data, we classify the collected immune genes into distinct categories: pattern recognition receptors, classical immune pathways, effector genes and others. In-depth data analysis has enabled us to predict some potential antiviral genes. Subsequently, we performed antiviral experiments on selected genes, exploring their impact on Bombyx mori nucleopolyhedrovirus replication. The outcomes of this research furnish novel insights into the immune genes of the silkworm, consequently fostering advancements in the field of silkworm immunity research by establishing a comprehensive classification and functional understanding of immune-related genes in the silkworm. This study contributes to the broader understanding of insect immune responses and opens up new avenues for future investigations in the domain of host-pathogen interactions.

Heterologous Effects of Pertussis and Influenza Vaccines During Pregnancy on Maternal and Infant Innate Immune Responses: A Pilot Study

BACKGROUND

Research has demonstrated that some vaccines may have effects on the immune system beyond their intended targets. These heterologous effects of vaccination occur through reprogramming of innate immune cells, resulting in enhanced cytokine responses to unrelated pathogens and have been observed most evidently following Bacillus Calmette-Guérin vaccination. Pregnant women in the United Kingdom are offered influenza and acellular pertussis (Tdap) vaccines to protect the mother and infant, respectively, from infection. Little is known about the potential heterologous effects of vaccines given during pregnancy on the maternal and infant immune systems.

OBJECTIVE

To investigate heterologous innate immune responses in mothers and infants from pertussis-vaccinated and pertussis/influenza double-vaccinated pregnancies compared with unvaccinated pregnancies, in a pilot cohort.

METHODS

In this pilot study, samples collected as part of 2 maternal immunization studies were utilized. Maternal and cord peripheral blood mononuclear cells (PBMCs) were collected at birth from women who had received both Tdap and influenza vaccination, only the Tdap vaccine or no vaccines during pregnancy. To further investigate the effect of influenza vaccination alone, PBMCs were collected from nonpregnant women before and after seasonal influenza vaccination. PBMCs were incubated with pattern recognition receptor (PRR) ligands, vaccine adjuvants or CRM197 for 24 hours and cytokine responses were quantified in supernatants by enzyme-linked immunosorbent assay.

RESULTS

PBMC from women who received both Tdap and influenza vaccines had reduced IL-1β, IL-6 and IL-8 cytokine responses to PRR ligand stimulation, compared with those from women who received Tdap alone. Maternal vaccine status during pregnancy did not impact cytokine responses to PRR stimulation in cord PBMCs. Seasonal influenza vaccination did not alter cytokine responses to PRR ligands in nonpregnant women.

CONCLUSIONS

Our pilot study suggests that PBMC from women receiving combined Tdap and influenza vaccination during pregnancy may have reduced in vitro cytokine responses to nonpertussis stimuli. Larger cohorts of mother-infant pairs need to be studied to confirm these findings, study the potential mechanisms and control for potential confounders.

TLR2-Bound Cancer-Secreted Hsp70 Induces MerTK-Mediated Immunosuppression and Tumorigenesis in Solid Tumors

Background: A hallmark of cancer is the presence of an immunosuppressive tumor microenvironment (TME). Immunosuppressive M2 macrophages (MΦs) in the TME facilitate escape from immune surveillance and promote tumor growth; therefore, TME-induced immunosuppression is a potent immunotherapeutic approach to treating cancer. Methods: Cancer cell-secreted proteins were detected by using liquid chromatography-mass spectrometry (LC-MS). Neutralizing antibodies (nAbs) were used to assess which proteins were involved in MΦs polarization and differentiation. The protein-protein interaction was characterized using co-immunoprecipitation and immunofluorescence assays. Cancer-secreted heat shock protein 70 (Hsp70) protein was quantified using an enzyme-linked immunosorbent assay (ELISA). MΦ polarization and tumor growth were assessed in vivo with subcutaneous LLC-GFP tumor models and toll-like receptor 2 (TLR2) knockout mice; in vitro assessments were conducted using TLR2 knockout and both LLC-GFP and LN227 lentiviral-mediated knockdown (KD) cells. Results: Cancer cells released a secreted form of Hsp70 that acted on MΦ TLR2 to upregulate Mer receptor tyrosine kinase (MerTK) and induce MΦ M2 polarization. Hsp70 nAbs led to a reduction in CD14 expression by 75% in THP-1 cells in response to Gli36 EMD-CM. In addition, neutralizing TLR2 nAbs resulted in a 30% and 50% reduction in CD14 expression on THP-1 cells in response to MiaPaCa-2 and Gli36 exosome/microparticle-depleted conditioned media (EMD-CMs), respectively. Hsp70, TLR2, and MerTK formed a protein complex. Tumor growth and intra-tumor M2 MΦs were significantly reduced upon cancer cell Hsp70 knockdown and in TLR2 knockout mice. Conclusions: Cancer-secreted Hsp70 interacts with TLR2, upregulates MerTK on MΦs, and induces immunosuppressive MΦ M2 polarization. This previously unreported action of secreted Hsp70 suggests that disrupting the Hsp70-TLR2-MerTK interaction could serve as a promising immunotherapeutic approach to mitigate TME immunosuppression in solid cancers.

Disruption of tumor-intrinsic PGAM5 increases anti-PD-1 efficacy through the CCL2 signaling pathway

BACKGROUND

Immunosuppressive phenotype compromised immunotherapy efficacy of hepatocellular carcinoma. Tumor cells intrinsic mitochondria dynamics could pass effects on the extracellular microenvironment through mtDNA stress. PGAM5 anchors at mitochondria and regulates mitochondria functions. We aim to explore whether the regulation of tumor-intrinsic PGAM5 on mitochondria affects tumor-infiltrating immune cells in the microenvironment and whether tumor-intrinsic PGAM5 can be a therapeutic target to enhance the immunotherapy efficacy of hepatocellular carcinoma (HCC).

METHODS

We analyzed the correlation of PGAM5 expression and immune cells infiltration using Gene Expression Omnibus (GEO) and The Cancer Genome Atlas Liver Hepatocellular Carcinoma (TCGA-LIHC) data sets based on cibersort algorithm and tumor-tissue arrays from two independent cohorts. To further validate our findings, we established subcutaneous and orthotopic mouse HCC models with tumor-intrinsic Pgam5 deficiency and analyzed tumor-infiltrating immune cells by flow cytometry and single-cell RNA sequencing. Mechanistically, we established an in vitro co-culture system and analyzed proteomics data to find out the bridge between tumor cell PGAM5 and tumor-associated macrophages (TAMs) in the microenvironment. Immunofluorescence, chromatin-immunoprecipitation, ELISA, mass spectrometry were conducted to explore the molecular pathway. Macrophages were depleted to investigate whether the effects of tumor-intrinsic PGAM5 on TAMs could affect immunotherapy efficacy in HCC orthotopic and subcutaneous mouse models.

RESULTS

PGAM5 expression in tumor was positively correlated with M2-phenotype TAM infiltration in patients with both HCC and mouse HCC tumor models. High tumor-intrinsic PGAM5 expression promoting M2 TAMs infiltration correlated with poor clinical-pathological characteristics and prognosis in patients with HCC. Disruption of tumor-intrinsic Pgam5 reduced TAM M2 polarization and inhibited HCC tumor growth in tumor-bearing mice. Mechanistically, in HCC cells PGAM5 deficiency inhibited mitochondria fission by promoting TRIM28 binding with DRP1, which increased ubiquitination and degradation of DRP1. Tumor-intrinsic PGAM5 deficiency mediated mitochondria fusion and reduced cytosolic mtDNA stress which attenuated TLR9 activation and downstream NF-κB-regulated CCL2 secretion. Furthermore, disruption of tumor-intrinsic Pgam5 significantly facilitated CD8+ T cells activation and improved anti-programmed cell death protein-1 therapeutic efficacy with macrophages depletion compromising synergistic antitumor immune response.

CONCLUSION

Our results shed light on the effect of tumor mitochondria dynamics on TAMs in tumor microenvironment. Tumor-intrinsic PGAM5 can be a therapeutic target to improve immunotherapy efficacy in patients with HCC.

DNA PAMPs as Molecular Tools for the cGAS-STING Signaling Pathways

Beyond its role as the bearer of genetic material, DNA also plays a crucial role in the activation phase of innate immunity. Pathogen recognition receptors (PRRs) and their homologs, pathogen-associated molecular patterns (PAMPs), form the foundation for driving innate immune activation and the induction of immune responses during infection. In the context of DNA viruses or bacterial infections, specific DNA sequences are recognized and bound by DNA sensors, marking the DNA as a PAMP for host recognition and subsequent activation of innate immunity. The primary DNA sensor pathway known to date is cGAS-STING, which can induce Type I interferons (IFN) and innate immune responses against viruses and bacteria. Additionally, the cGAS-STING pathway has been identified to mediate functions in autophagy and senescence. Herein, we introduce methods for using DNA PAMPs as molecular tools to study the role of cGAS-STING and its signaling pathway in regulating innate immunity, both in vitro and in vivo.

Toll-like receptor agonists as cancer vaccine adjuvants

Cancer immunotherapy has emerged as a promising strategy to treat cancer patients. Among the wide range of immunological approaches, cancer vaccines have been investigated to activate and expand tumor-reactive T cells. However, most cancer vaccines have not shown significant clinical benefit as monotherapies. This is likely due to the antigen targets of vaccines, "self" proteins to which there is tolerance, as well as to the immunosuppressive tumor microenvironment. To help circumvent immune tolerance and generate effective immune responses, adjuvants for cancer vaccines are necessary. One representative adjuvant family is Toll-Like receptor (TLR) agonists, synthetic molecules that stimulate TLRs. TLRs are the largest family of pattern recognition receptors (PRRs) that serve as the sensors of pathogens or cellular damage. They recognize conserved foreign molecules from pathogens or internal molecules from cellular damage and propel innate immune responses. When used with vaccines, activation of TLRs signals an innate damage response that can facilitate the development of a strong adaptive immune response against the target antigen. The ability of TLR agonists to modulate innate immune responses has positioned them to serve as adjuvants for vaccines targeting infectious diseases and cancers. This review provides a summary of various TLRs, including their expression patterns, their functions in the immune system, as well as their ligands and synthetic molecules developed as TLR agonists. In addition, it presents a comprehensive overview of recent strategies employing different TLR agonists as adjuvants in cancer vaccine development, both in pre-clinical models and ongoing clinical trials.

Dendritic cell activation by iron oxide nanoparticles depends on the extracellular environment

Nanoparticles can exert immune modulating effects in a host depending on composition, mode of administration, and type of disease. Although the specific mechanisms of nanoparticle-induced immune responses remain unclear, their uptake by macrophages and other phagocytic innate immune cells is considered to be a key event. Our objective here was to ascertain if nanoparticle-mediated activation of dendritic cells (DCs) occurs in vitro or in vivo when exposed to hydroxyethyl starch-coated iron oxide nanoparticles. For the present studies, our choice of nanoparticles, animal model, and experimental design is motivated by our previously published observations that systemic exposure can induce antitumor adaptive immune responses in mouse models of metastatic breast cancer. Here, we began by assessing the potential toxicity of systemic exposure to commercially available starch-coated Bionized Nanoferrite® nanoparticles (BP) by measuring body weight, complete blood count, and enzyme parameters in healthy FVB/NJ mice after repeated BP dosing. We observed no evidence of toxicity at doses up to 25 mg Fe per mouse, five-fold higher than those used in subsequent in vivo experiments. We then measured the expression of surface maturation markers (CD86, MHC II) in DCs incubated with BP in vitro. Although DCs cultured with BP revealed high levels of nanoparticle uptake, neither JAWSII dendritic cells nor bone marrow derived dendritic cells (BMDCs) showed significant changes in marker expression to indicate stimulation of maturation and effector function. To assess whether BP interactions in vivo produced different effects, we analyzed CD80, CD86, and MHC II expression of DCs recovered from the livers, spleens, bone marrows, and lymph nodes of mice injected once with BP (5 mg Fe). Interestingly, only DCs in spleens and bone marrow cells responded to BP exposure. DCs recovered from other organs showed no evidence of increased activation. These findings highlight complex interactions between living systems and nanoparticles, and their potential to mediate context-specific and selective activation of innate immune cells. Our study also emphasizes that results obtained from in vitro experiments must be interpreted with caution, as they may not faithfully represent responses in living systems.

Insight into the role of macrophages in periodontitis restoration and development

Periodontitis is one of the chronic diseases that have the greatest impact on human health, and it is associated with several other chronic diseases. Tissue damage associated with periodontitis is often connected with immune response. Immune cells are a crucial component of the human immune system and are directly involved in periodontitis during the inflammatory phase of the disease. Macrophages, as a key component of the immune system, are responsible for defence, antigen presentation and phagocytosis in healthy tissue. They are also closely linked to the development and resolution of periodontitis, through mechanisms such as macrophage polarization, pattern recognition receptors recognition, efferocytosis, and Specialized Pro-resolving Mediators (SPMs) production. Additionally, apoptosis and autophagy are also known to play a role in the recovery of periodontitis. This review aims to investigate the aforementioned mechanisms in more detail and identify novel therapeutic approaches for periodontitis.

Positive Selection of TLR2 and MyD88 Genes Provides Insights Into the Molecular Basis of Immunological Adaptation in Amphibians

The transition from water to land of amphibians is evolutionarily significant in the history of vertebrates, and immunological adaptation is an important challenge for amphibians to respond to the dramatic changes of the environmental pathogens during their origin and diversification. Toll-like receptors (TLRs) are important pattern recognition receptors for the innate immune response and TLRs signaling pathway play essential roles in the immune responses to pathogens and inflammatory reaction. However, the evolutionary patterns and molecular mechanisms underlying their adaptation in amphibians are poorly documented to date. Here, we determined the coding regions, expression patterns of TLR2 and Myeloid differentiation factor 88 (MyD88) in the large treefrog (Zhangixalus dennysi), and explored the evolutionary patterns of these two genes in amphibians. Quantitative Real-time PCR analyses showed that the TLR2 and MyD88 mRNA were expressed in all the organs/tissues examined, both with the highest levels in the heart and the lowest levels in the body fat for TLR2 and lung for MyD88. The highly conservation and functional significance of these two genes in amphibians were supported based on the sequence characteristics and evolutionary analyses. Significantly positive selection was found to be acting on TLR2 and MyD88 in amphibians based on different site models. Strong signal of positive selection among different amphibian lineages for these two genes was also detected and a series of positively selected sites were identified based on the branch-site analysis. Our results suggest that amphibians have adapted to different pathogenic microorganisms during their transition from the aquatic to terrestrial environment and diversification into various habitats. The present study will provide new insights into the evolutionary process and molecular basis underlying the immunological adaptation in vertebrates.

Inflammatory pathways and anti-inflammatory therapies in sickle cell disease

Sickle cell disease (SCD) is a monogenic disease, resulting from a single-point mutation, that presents a complex pathophysiology and high clinical heterogeneity. Inflammation stands as a prominent characteristic of SCD. Over the past few decades, the role of different cells and molecules in the regulation of the inflammatory process has been elucidated. In conjunction with the polymerization of hemoglobin S (HbS), intravascular hemolysis, which releases free heme, HbS, and hemoglobin-related damage-associated molecular patterns, initiates multiple inflammatory pathways that are not yet fully comprehended. These complex phenomena lead to a vicious cycle that perpetuates vaso-occlusion, hemolysis, and inflammation. To date, few inflammatory biomarkers can predict disease complications; conversely, there is a plethora of therapies that reduce inflammation in SCD, although clinical outcomes vary widely. Importantly, whether the clinical heterogeneity and complications are related to the degree of inflammation is not known. This review aims to further our understanding of the roles of main immune cells, and other inflammatory factors, as potential prognostic biomarkers for predicting clinical outcomes or identifying novel treatments for SCD.

Exploring the Characteristics of Gut Microbiota Associated with Depression via the Depression Assessment Scales

Depression is a prevalent mental disorder with an increasing economic burden, and its pathogenesis remains poorly understood. Given the emerging evidence linking the gut microbiota to mental health, a better understanding of microbial profiles associated with depression is necessary. Here, we explore the association between gut microbiota and depression by utilizing 16S rRNA amplicon sequencing and depression assessment scales, including the Hamilton Depression Rating Scale (HDRS) and the Beck Depression Inventory (BDI). The study cohort consisted of 46 subjects, who were categorized into depression and normal groups based on medical diagnoses and depression scale scores. Our analyses revealed that HDRS-based classification better identified distinct gut microbiota structures associated with depression than medical diagnoses alone. Notably, lower beta diversity was observed in individuals with depression, indicating a more homogeneous gut microbial community. By employing both HDRS and BDI scores simultaneously, we identified specific taxa, such as Bilophila and Alistipes, which are linked to depressive symptoms. These findings highlight the potential of using depression assessment scales in conjunction with gut microbiota data to advance our understanding of depression and inform future treatment strategies.

Pattern recognition receptors in Crustacea: immunological roles under environmental stress

Innate immunity is the first line of defense against infections and the only known available strategy for invertebrates. Crustaceans, being mostly aquatic invertebrates, are constantly exposed to potential pathogens in the surrounding water. Their immune system abolishes most microbes that enter and are recognized as a threat. However, the stress produced by high population densities and abiotic changes, in aquaculture, disrupts the host-pathogen balance, leading to severe economic losses in this industry. Consequently, crustacean immunology has become a prime area of research where significant progress has been made. This review provides our current understanding of the key pattern recognition receptors in crustaceans, with special focus on Decapoda, and their roles in triggering an immune response. We discuss recent developments in the field of signal transduction pathways such as Toll-like receptors (TLRs) and the immune deficiency (IMD) pathway, and examine the role of antimicrobial peptides (AMPs) in pathogen defense. Additionally, we analyze how environmental stressors-such as temperature fluctuations, ammonia levels, and pollution-impact immune responses and increase susceptibility to diseases. Finally, we highlight future research directions, emphasizing the need to explore the interactions between environmental stressors and immune signaling pathways and to develop strategies to enhance immune responses in crustaceans within aquaculture settings. Altogether, these advancements deepen our understanding of pathogen recognition in invertebrates and the specific defense mechanisms employed by crustaceans, particularly in response to infections triggered by pathogens under abiotic stressors.

17β-estradiol inhibits Notch1 activation in murine macrophage cell line RAW 264.7

BACKGROUND

Macrophages are major effectors in regulating immune response and inflammation. The pro-inflammatory phenotype (M1) is induced by the activation of the Toll-like receptor 4 (TLR4) on the macrophage surface, which recognizes lipopolysaccharide (LPS), a component of Gram-negative bacterial wall, and by the binding of interferon-gamma (IFNγ), a cytokine released by activated T lymphocytes, to its receptor (IFNGR). Among the pathways activated by LPS/IFNγ is the Notch pathway, which promotes the M1 phenotype. Conversely, 17β-estradiol (E2) has been shown to blunt LPS-mediated inflammatory response. While it has been shown that E2 regulates the activity of the Notch1 receptor in human endothelial cells, there is no evidence of estrogen-mediated regulation of Notch1 in macrophages.

METHODS AND RESULTS

In this study, RAW 264.7 cells were stimulated with LPS/IFNγ in the presence or absence of E2 and/or N-[N-(3,5-difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester (DAPT), an inhibitor of γ-secretase, the enzyme involved in Notch activation. The effects of treatment on inducible nitric oxide synthase (iNOS), on components of the Notch pathway, and MAPK (mitogen-activated protein kinase) were assessed by quantitative PCR and Western blotting. We found that E2, through a mechanism involving the inhibition of p38 phosphorylation, reduces the activation of Notch1 induced by LPS/IFNγ. On the contrary, Notch1 exerts a negative control on the estrogen receptor α (ERα) since Notch1 inhibition increases the protein levels of this receptor.

CONCLUSION

In conclusion, we report for the first time a Notch-ERα interaction in macrophages. Our data suggest that E2 may reduce LPS/IFNγ-mediated M1 pro-inflammatory phenotype in macrophages by inhibiting Notch1. This finding encourages further studies on Notch1 inhibitors as novel treatments for inflammation-related diseases.

An Integrated Signaling Threshold Initiates IgG Response toward Virus-like Immunogens

Class-switched neutralizing Ab (nAb) production is rapidly induced upon many viral infections. However, due to the presence of multiple components in virions, the precise biochemical and biophysical signals from viral infections that initiate nAb responses remain inadequately defined. Using a reductionist system of synthetic virus-like structures, in this study, we show that a foreign protein on a virion-sized liposome can serve as a stand-alone danger signal to initiate class-switched nAb responses without T cell help or TLR but requires CD19. Introduction of internal nucleic acids (iNAs) obviates the need for CD19, lowers the epitope density (ED) required to elicit the Ab response, and transforms these structures into highly potent immunogens that rival conventional virus-like particles in their ability to elicit strong Ag-specific IgG. As early as day 5 after immunization, structures harboring iNAs and decorated with just a few molecules of surface Ag at doses as low as 100 ng induced all IgG subclasses of Ab in mice and reproduced the IgG2a/2c restriction that is long observed in live viral infections. These findings reveal a shared mechanism for the nAb response in mice. High ED is capable but not necessary for driving Ab secretion. Instead, even a few molecules of surface Ag, when combined with nucleic acids within these structures, can trigger strong IgG production. As a result, the signaling threshold for induction of IgG in individual B cells is set by dual signals originating from both ED on the surface and the presence of iNAs within viral particulate immunogens.

Protein kinase D1 in myeloid lineage cells contributes to the accumulation of CXCR3+CCR6+ nonconventional Th1 cells in the lungs and potentiates hypersensitivity pneumonitis caused by S. rectivirgula

Introduction

Hypersensitivity pneumonitis (HP) is an extrinsic allergic alveolitis characterized by inflammation of the interstitium, bronchioles, and alveoli of the lung that leads to granuloma formation. We previously found that activation of protein kinase D1 (PKD1) in the lungs following exposures to Saccharopolyspora rectivirgula contributes to the acute pulmonary inflammation, IL-17A expression in the lungs, and development of HP. In the present study, we investigated whether PKD1 in myeloid-lineage cells affects the pathogenic course of the S. rectivirgula-induced HP.

Methods

Mice were exposed intranasally to S. rectivirgula once or 3 times/week for 3 weeks. The protein and mRNA expression levels of cytokines/chemokines were detected by enzyme-linked immunosorbent assay and quantitative real-time PCR, respectively. Flow cytometry was used to detect the different types of immune cells and the levels of surface proteins. Lung tissue sections were stained with hematoxylin and eosin, digital images were captured, and immune cells influx into the interstitial lung tissue were detected.

Results

Compared to control PKD1-sufficient mice, mice with PKD1 deficiency in myeloid-lineage cells (PKD1mKO) showed significantly suppressed expression of TNFα, IFNγ, IL-6, CCL2, CCL3, CCL4, CXCL1, CXCL2, and CXCL10 and neutrophilic alveolitis after single intranasal exposure to S. rectivirgula. Substantially reduced levels of alveolitis and granuloma formation were observed in the PKD1mKO mice repeatedly exposed to S. rectivirgula for 3 weeks. In addition, expression levels of the Th1/Th17 polarizing cytokines and chemokines such as IFNγ, IL-17A, CXCL9, CXCL10, CXCL11, and CCL20 in lungs were significantly reduced in the PKD1mKO mice repeatedly exposed to S. rectivirgula. Moreover, accumulation of CXCR3+CCR6+ nonconventional Th1 in the lungs were significantly reduced in PKD1mKO mice repeatedly exposed to S. rectivirgula.

Discussion

Our results demonstrate that PKD1 in myeloid-lineage cells plays an essential role in the development and progress of HP caused by repeated exposure to S. rectivirgula by contributing Th1/Th17 polarizing proinflammatory responses, alveolitis, and accumulation of pathogenic nonconventional Th1 cells in the lungs.

Haptoglobin buffers lipopolysaccharides to delay activation of NFκB

It has remained yet unclear which soluble factors regulate the anti-inflammatory macrophage phenotype observed in both homeostasis and tumourigenesis. We show here that haptoglobin, a major serum protein with elusive immunoregulatory properties, binds and buffers bacterial lipopolysaccharides to attenuate activation of NFκB in macrophages. Haptoglobin binds different lipopolysaccharides with low micromolar affinities. Given its abundance, haptoglobin constitutes a buffer for serum-borne lipopolysaccharides, shielding them to safeguard against aberrant inflammatory reactions by reducing the amount of free lipopolysaccharides available for binding to TLR4. Concordantly, NFκB activation by haptoglobin-associated lipopolysaccharides was markedly delayed relative to stimulation with pure lipopolysaccharide. Our findings warrant evaluation of therapeutic benefits of haptoglobin for inflammatory conditions and re-evaluation of purification strategies. Finally, they allow to elucidate mechanisms of enhanced immunosuppression by oncofetal haptoglobin.

Epidemiological and genetic aspects of pulmonary tuberculosis in Kazakhstan

OBJECTIVE

Tuberculosis is a major health problem in many countries, including Kazakhstan. Host genetics can affect TB risk, and epidemiological and social factors may contribute to disease progression. Due to the high incidence of pulmonary tuberculosis in the country, our research aimed to study the epidemiological and genetic aspects of pulmonary tuberculosis in Kazakhstan.

MATERIAL AND METHODS

1026 participants of Central Asian origin were recruited in the study: 342 individuals diagnosed with active PTB, 342 household contacts, and 342 controls without a family history of TB. Genetic polymorphisms of selected genes were determined by real-time polymerase chain reaction. The association between the risk of pulmonary TB and polymorphisms was evaluated using logistic regression and assessed with the ORs and their corresponding 95 % CIs, and the significance level was determined as p < 0.05.

RESULTS

Epidemiological data revealed that underweight BMI (χ² = 89.97, p < 0.001), employment (χ² = 39.28, p < 0.001), and diabetes (χ² = 12.38, p < 0.001) showed a significant association with PTB. A/T polymorphism of the IFG gene showed a lower risk, and A/A polymorphism showed an increased risk of susceptibility to TB. A/A polymorphism of the IFG gene was associated with an almost 3-fold increased risk of PTB, and A/T polymorphism of the IFG gene was associated with a decreased risk of PTB (OR = 0.67, 95 % CI = 0.49-0.92, p = 0.01). The analysis revealed a decreased risk of PTB for A/A polymorphism of the VDR ApaI (OR = 0.67, 95 % CI = 0.46-0.97, p < 0.05). A/A polymorphism of the TLR8 gene was associated with a 1.5-fold increased risk of PTB (OR = 1.53, 95 % CI = 1.00-2.33, p < 0.05).

CONCLUSION

Results showed that gender, employment, underweight BMI and diabetes are associated with PTB incidence in our study cohort. The A/A genotype of the IFG (rs2430561) and an A/A genotype of the TLR8 (rs3764880) genes were associated with an increased risk of PTB. A/T polymorphism of the IFG (rs2430561) and A/A polymorphism of the VDR ApaI were associated with a decreased risk of PTB.

Cloning and Functional Characterization of Novel Human Neutralizing Anti-IFN-α and Anti-IFN-β Antibodies

Type I IFNs play a pivotal role in immune response modulation, yet dysregulation is implicated in various disorders. Therefore, it is crucial to develop tools that facilitate the understanding of their mechanism of action and enable the development of more effective anti-IFN therapeutic strategies. In this study, we isolated, cloned, and characterized anti-IFN-α and anti-IFN-β Abs from PBMCs of individuals treated with IFN-α or IFN-β, harboring confirmed neutralizing Abs. Clones AH07856 and AH07857 were identified as neutralizing anti-IFN-α-specific with inhibition against IFN-α2a, -α2b, and -αK subtypes. Clones AH07859 and AH07866 were identified as neutralizing anti-IFN-β1a-specific signaling and able to block lipopolysaccharide or S100 calcium-binding protein A14-induced IFN-β signaling effects. Cloned Abs bind rhesus but not murine IFNs. The specificity of inhibition between IFN-α and IFN-β suggests potential for diverse research and clinical applications.

Coxsackievirus B3 Activates Macrophages Independently of CAR-Mediated Viral Entry

Enteroviruses are a genus of small RNA viruses that are responsible for approximately one billion global infections annually. These infections range in severity from the common cold and flu-like symptoms to more severe diseases, such as viral myocarditis, pancreatitis, and neurological disorders, that continue to pose a global health challenge with limited therapeutic strategies currently available. In the current study, we sought to understand the interaction between coxsackievirus B3 (CVB3), which is a model enterovirus, and macrophage cells, as there is limited understanding of how this virus interacts with macrophage innate immune cells. Our study demonstrated that CVB3 can robustly activate macrophages without apparent viral replication in these cells. We also showed that myeloid cells lacked the viral entry receptor coxsackievirus and adenovirus receptor (CAR). However, the expression of exogenous CAR in RAW264.7 macrophages was unable to overcome the viral replication deficit. Interestingly, the CAR expression was associated with altered inflammatory responses during prolonged infection. Additionally, we identified the autophagy protein LC3 as a novel stimulus for macrophage activation. These findings provide new insights into the mechanisms of CVB3-induced macrophage activation and its implications for viral pathogenesis.

TLR4 induced TRPM2 mediated neuropathic pain

Ion channels play an important role in mediating pain through signal transduction, regulation, and control of responses, particularly in neuropathic pain. Transient receptor potential channel superfamily plays an important role in cation permeability and cellular signaling. Transient receptor potential channel Melastatin 2 (TRPM2) subfamily regulates Ca2+ concentration in response to various chemicals and signals from the surrounding environment. TRPM2 has a role in several physiological functions such as cellular osmosis, temperature sensing, cellular proliferation, as well as the manifestation of many disease processes such as pain process, cancer, apoptosis, endothelial dysfunction, angiogenesis, renal and lung fibrosis, and cerebral ischemic stroke. Toll-like Receptor 4 (TLR4) is a critical initiator of the immune response to inflammatory stimuli, particularly those triggered by Lipopolysaccharide (LPS). It activates downstream pathways leading to the production of oxidative molecules and inflammatory cytokines, which are modulated by basal and store-operated calcium ion signaling. The cytokine production and release cause an imbalance of antioxidant enzymes and redox potential in the Endoplasmic Reticulum and mitochondria due to oxidative stress, which results from TLR-4 activation and consequently induces the production of inflammatory cytokines in neuronal cells, exacerbating the pain process. Very few studies have reported the role of TRPM2 and its association with Toll-like receptors in the context of neuropathic pain. However, the molecular mechanism underlying the interaction between TRPM2 and TLR-4 and the quantum of impact in acute and chronic neuropathic pain remains unclear. Understanding the link between TLR-4 and TRPM2 will provide more insights into pain regulation mechanisms for the development of new therapeutic molecules to address neuropathic pain.

Inhibition of ULK1/2 and KRASG12C controls tumor growth in preclinical models of lung cancer

Mutational activation of KRAS occurs commonly in lung carcinogenesis and, with the recent U.S. Food and Drug Administration approval of covalent inhibitors of KRASG12C such as sotorasib or adagrasib, KRAS oncoproteins are important pharmacological targets in non-small cell lung cancer (NSCLC). However, not all KRASG12C-driven NSCLCs respond to these inhibitors, and the emergence of drug resistance in those patients who do respond can be rapid and pleiotropic. Hence, based on a backbone of covalent inhibition of KRASG12C, efforts are underway to develop effective combination therapies. Here, we report that the inhibition of KRASG12C signaling increases autophagy in KRASG12C-expressing lung cancer cells. Moreover, the combination of DCC-3116, a selective ULK1/2 inhibitor, plus sotorasib displays cooperative/synergistic suppression of human KRASG12C-driven lung cancer cell proliferation in vitro and superior tumor control in vivo. Additionally, in genetically engineered mouse models of KRASG12C-driven NSCLC, inhibition of either KRASG12C or ULK1/2 decreases tumor burden and increases mouse survival. Consequently, these data suggest that ULK1/2-mediated autophagy is a pharmacologically actionable cytoprotective stress response to inhibition of KRASG12C in lung cancer.

Targeting Myeloid Differentiation Primary Response Protein 88 (MyD88) and Galectin-3 to Develop Broad-Spectrum Host-Mediated Therapeutics against SARS-CoV-2

Nearly six million people worldwide have died from the coronavirus disease (COVID-19) outbreak caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Although COVID-19 vaccines are largely successful in reducing the severity of the disease and deaths, the decline in vaccine-induced immunity over time and the continuing emergence of new viral variants or mutations underscore the need for an alternative strategy for developing broad-spectrum host-mediated therapeutics against SARS-CoV-2. A key feature of severe COVID-19 is dysregulated innate immune signaling, culminating in a high expression of numerous pro-inflammatory cytokines and chemokines and a lack of antiviral interferons (IFNs), particularly type I (alpha and beta) and type III (lambda). As a natural host defense, the myeloid differentiation primary response protein, MyD88, plays pivotal roles in innate and acquired immune responses via the signal transduction pathways of Toll-like receptors (TLRs), a type of pathogen recognition receptors (PRRs). However, recent studies have highlighted that infection with viruses upregulates MyD88 expression and impairs the host antiviral response by negatively regulating type I IFN. Galectin-3 (Gal3), another key player in viral infections, has been shown to modulate the host immune response by regulating viral entry and activating TLRs, the NLRP3 inflammasome, and NF-κB, resulting in the release of pro-inflammatory cytokines and contributing to the overall inflammatory response, the so-called "cytokine storm". These studies suggest that the specific inhibition of MyD88 and Gal3 could be a promising therapy for COVID-19. This review presents future directions for MyD88- and Gal3-targeted antiviral drug discovery, highlighting the potential to restore host immunity in SARS-CoV-2 infections.

Investigation of Thiol/Disulfide Homeostasis and Clinical Parameters in Rosacea Patients According to Skin Subtypes

Background/Objective: The aim of this study was to compare thiol/disulfide homeostasis and clinical parameters of rosacea patients across skin subtypes of the disease and healthy controls. Methods: This prospective study included 90 rosacea patients with different skin subtypes (phymatous, erythematotelangiectatic and papulopustular) and ocular involvement and 30 healthy controls. Plasma native thiol (NT), total thiol (TT) and disulfide levels of the patients and controls were measured using an automated spectrophotometric method, and disulfide/native thiol ratio (DNTR), disulfide/total thiol ratio (DTTR) and native thiol/total thiol ratio (NTTR) were calculated. Tear breakup time (TBUT), meiboscore, Schirmer, ocular surface disease index (OSDI) and rosacea-specific quality of life scale (RosaQoL) were measured clinically. Results: Disulfide, DNTR and DTTR were significantly higher, and NT, TT and NTTR were significantly lower in the rosacea patients compared to the controls (p < 0.001). TBUT and Schirmer were significantly lower, and meiboscore and OSDI were significantly higher in the patients compared to the controls (p < 0.01). According to the skin subtypes, disulfide, DNTR and DTTR were significantly higher, and NTTR was significantly lower in the erythematotelangiectatic subtype compared to the other subtypes (p < 0.002). TBUT was significantly lower, and RosaQol was significantly higher in the erythematotelangiectatic subtype (p < 0.0083). Strong correlations were found between DNTR and TBUT and between DNTR and Meiboscore in all subtypes (p < 0.005), while there were strong correlations between DNTR and OSDI and between DNTR and RosaQol only in the erythematotelangiectatic and papulopustular subtypes (p < 0.05). Conclusions: The thiol/disulfide homeostasis shifted towards disulfides, an indicator of oxidative stress in rosacea, and this was more pronounced in the erythematotelangiectatic subtype. The impairment in TBUT and RosaQol was also more prominent in the erythematotelangiectatic subtype and strongly associated with the DNTR.

NLRP3 inflammasome signalling in Alzheimer's disease

Every year, 10 million people develop dementia, the most common of which is Alzheimer's disease (AD). To date, there is no way to prevent cognitive decline and therapies are limited. This review provides a neuroimmunological perspective on the progression of AD, and discusses the immune-targeted therapies that are in preclinical and clinical trials that may impact the development of this disease. Specifically, we look to the role of the NLRP3 inflammasome, its triggers in the brain and how its activation can contribute to the progression of dementia. We summarise the range of inhibitors targeting the NLRP3 inflammasome and its downstream pathways that are under investigation, and discuss future therapeutic perspectives for this devastating condition.

The emerging role of adaptor proteins in regulating innate immunity of sepsis

Sepsis is a life-threatening syndrome caused by a dysregulated immune response. A large number of adaptor proteins have been found to play a pivotal role in sepsis via protein-protein interactions, thus participating in inflammatory cascades, leading to the generation of numerous inflammatory cytokines, as well as oxidative stress and regulated cell death. Although available strategies for the diagnosis and management of sepsis have improved, effective and specific treatments are lacking. This review focuses on the emerging role of adaptor proteins in regulating the innate immunity of sepsis and evaluates the potential value of adaptor protein-associated therapeutic strategy for sepsis.

Inhibition of ULK1/2 and KRAS G12C controls tumor growth in preclinical models of lung cancer

Mutational activation of KRAS occurs commonly in lung carcinogenesis and, with the recent FDA approval of covalent inhibitors of KRAS G12C such as sotorasib or adagrasib, KRAS oncoproteins are important pharmacological targets in non-small cell lung cancer (NSCLC). However, not all KRAS G12C -driven NSCLCs respond to these inhibitors, and the emergence of drug resistance in those patients that do respond can be rapid and pleiotropic. Hence, based on a backbone of covalent inhibition of KRAS G12C , efforts are underway to develop effective combination therapies. Here we report that inhibition of KRAS G12C signaling increases autophagy in KRAS G12C expressing lung cancer cells. Moreover, the combination of DCC-3116, a selective ULK1/2 inhibitor, plus sotorasib displays cooperative/synergistic suppression of human KRAS G12C -driven lung cancer cell proliferation in vitro and superior tumor control in vivo . Additionally, in genetically engineered mouse models of KRAS G12C -driven NSCLC, inhibition of either KRAS G12C or ULK1/2 decreases tumor burden and increases mouse survival. Consequently, these data suggest that ULK1/2-mediated autophagy is a pharmacologically actionable cytoprotective stress response to inhibition of KRAS G12C in lung cancer.