A cell biological view of Toll-like receptor function: regulation through compartmentalization

Design and Optimization of Selectivity-Tunable Toll-like Receptor 7/8 Agonists as Novel Antibody-Drug Conjugate Payloads

Toll-like receptors 7 and 8 are involved in modulating the adaptive and innate immune responses, and their activation has shown promise as a therapeutic strategy in the field of immuno-oncology. While systemic exposure to TLR7/8 agonists can result in poor tolerance, combination therapies and targeted delivery through antibody-drug conjugates (ADCs) can help mitigate adverse effects. Described herein is the identification of a novel and potent series of pyrazolopyrimidine-based TLR7/8 agonists with tunable receptor selectivity. Representative agonists from this series were successfully able to induce the production of various proinflammatory cytokines and chemokines from human peripheral blood mononuclear cells. Anti-HER2-25 and anti-HER2-26 ADCs made from this class of payloads demonstrated mechanism-based activation of TLR7/8 in a THP1/N87 coculture system.

The Role of Viruses in the Pathogenesis of Immune-Mediated Gastro-Intestinal Diseases

Immune-mediated gastrointestinal (GI) diseases, including achalasia, celiac disease, and inflammatory bowel diseases, pose significant challenges in diagnosis and management due to their complex etiology and diverse clinical manifestations. While genetic predispositions and environmental factors have been extensively studied in the context of these conditions, the role of viral infections and virome dysbiosis remains a subject of growing interest. This review aims to elucidate the involvement of viral infections in the pathogenesis of immune-mediated GI diseases, focusing on achalasia and celiac disease, as well as the virome dysbiosis in IBD. Recent evidence suggests that viral pathogens, ranging from common respiratory viruses to enteroviruses and herpesviruses, may trigger or exacerbate achalasia and celiac disease by disrupting immune homeostasis in the GI tract. Furthermore, alterations in the microbiota and, specifically, in the virome composition and viral-host interactions have been implicated in perpetuating chronic intestinal inflammation in IBD. By synthesizing current knowledge on viral contributions to immune-mediated GI diseases, this review aims to provide insights into the complex interplay between viral infections, host genetics, and virome dysbiosis, shedding light on novel therapeutic strategies aimed at mitigating the burden of these debilitating conditions on patients' health and quality of life.

Immune-related gene methylation prognostic instrument for stratification and targeted treatment of ovarian cancer patients toward advanced 3PM approach

Background

DNA methylation is an important mechanism in epigenetics, which can change the transcription ability of genes and is closely related to the pathogenesis of ovarian cancer (OC). We hypothesize that DNA methylation is significantly different in OCs compared to controls. Specific DNA methylation status can be used as a biomarker of OC, and targeted drugs targeting these methylation patterns and DNA methyltransferase may have better therapeutic effects. Studying the key DNA methylation sites of immune-related genes (IRGs) in OC patients and studying the effects of these methylation sites on the immune microenvironment may provide a new method for further exploring the pathogenesis of OC, realizing early detection and effective monitoring of OC, identifying effective biomarkers of DNA methylation subtypes and drug targets, improving the efficacy of targeted drugs or overcoming drug resistance, and better applying it to predictive diagnosis, prevention, and personalized medicine (PPPM; 3PM) of OC.

Method

Hypermethylated subtypes (cluster 1) and hypomethylated subtypes (cluster 2) were established in OCs based on the abundance of different methylation sites in IRGs. The differences in immune score, immune checkpoints, immune cells, and overall survival were analyzed between different methylation subtypes in OC samples. The significant pathways, gene ontology (GO), and protein-protein interaction (PPI) network of the identified methylation sites in IRGs were enriched. In addition, the immune-related methylation signature was constructed with multiple regression analysis. A methylation site model based on IRGs was constructed and verified.

Results

A total of 120 IRGs with 142 differentially methylated sites (DMSs) were identified. The DMSs were clustered into a high-level methylation group (cluster 1) and a low-level methylation group (cluster 2). The significant pathways and GO analysis showed many immune-related and cancer-associated enrichments. A methylation site signature based on IRGs was constructed, including RORC|cg25112191, S100A13|cg14467840, TNF|cg04425624, RLN2|cg03679581, and IL1RL2|cg22797169. The methylation sites of all five genes showed hypomethylation in OC, and there were statistically significant differences among RORC|cg25112191, S100A13|cg14467840, and TNF|cg04425624 (p < 0.05). This prognostic model based on low-level methylation and high-level methylation groups was significantly linked to the immune microenvironment as well as overall survival in OC.

Conclusions

This study provided different methylation subtypes for OC patients according to the methylation sites of IRGs. In addition, it helps establish a relationship between methylation and the immune microenvironment, which showed specific differences in biological signaling pathways, genomic changes, and immune mechanisms within the two subgroups. These data provide ones to deeply understand the mechanism of immune-related methylation genes on the occurrence and development of OC. The methylation-site signature is also to establish new possibilities for OC therapy. These data are a precious resource for stratification and targeted treatment of OC patients toward an advanced 3PM approach.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13167-024-00359-3.

Unraveling the Complexities of Toll-like Receptors: From Molecular Mechanisms to Clinical Applications

Toll-like receptors (TLRs) are vital components of the innate immune system, serving as the first line of defense against pathogens by recognizing a wide array of molecular patterns. This review summarizes the critical roles of TLRs in immune surveillance and disease pathogenesis, focusing on their structure, signaling pathways, and implications in various disorders. We discuss the molecular intricacies of TLRs, including their ligand specificity, signaling cascades, and the functional consequences of their activation. The involvement of TLRs in infectious diseases, autoimmunity, chronic inflammation, and cancer is explored, highlighting their potential as therapeutic targets. We also examine recent advancements in TLR research, such as the development of specific agonists and antagonists, and their application in immunotherapy and vaccine development. Furthermore, we address the challenges and controversies surrounding TLR research and outline future directions, including the integration of computational modeling and personalized medicine approaches. In conclusion, TLRs represent a promising frontier in medical research, with the potential to significantly impact the development of novel therapeutic strategies for a wide range of diseases.

ACE mRNA (Additional Chimeric Element incorporated IVT mRNA) for Enhancing Protein Expression by Modulating Immunogenicity

The development of in vitro transcribed mRNA (IVT mRNA)-based therapeutics/vaccines depends on the management of IVT mRNA immunogenicity. IVT mRNA, which is used for intracellular protein translation, often triggers unwanted immune responses, interfering with protein expression and leading to reduced therapeutic efficacy. Currently, the predominant approach for mitigating immune responses involves the incorporation of costly chemically modified nucleotides like pseudouridine (Ψ) or N1-methylpseudouridine (m1Ψ) into IVT mRNA, raising concerns about expense and the potential misincorporation of amino acids into chemically modified codon sequences. Here, an Additional Chimeric Element incorporated mRNA (ACE mRNA), a novel approach incorporating two segments within a single IVT mRNA structure, is introduced. The first segment retains conventional IVT mRNA components prepared with unmodified nucleotides, while the second, comprised of RNA/DNA chimeric elements, aims to modulate immunogenicity. Notably, ACE mRNA demonstrates a noteworthy reduction in immunogenicity of unmodified IVT mRNA, concurrently demonstrating enhanced protein expression efficiency. The reduced immune responses are based on the ability of RNA/DNA chimeric elements to restrict retinoic acid-inducible gene I (RIG-I) and stimulator of interferon genes (STING)-mediated immune activation. The developed ACE mRNA shows great potential in modulating the immunogenicity of IVT mRNA without the need for chemically modified nucleotides, thereby advancing the safety and efficacy of mRNA-based therapeutics/vaccines.

NADPH oxidase exerts a B cell-intrinsic contribution to lupus risk by modulating endosomal TLR signals

Genome-wide association studies in systemic lupus erythematosus (SLE) have linked loss-of-function mutations in phagocytic NADPH oxidase complex (NOX2) genes, including NCF1 and NCF2, to disease pathogenesis. The prevailing model holds that reduced NOX2 activity promotes SLE via defective efferocytosis, the immunologically silent clearance of apoptotic cells. Here, we describe a parallel B cell-intrinsic mechanism contributing to breaks in tolerance. In keeping with an important role for B cell Toll-like receptor (TLR) pathways in lupus pathogenesis, NOX2-deficient B cells exhibit enhanced signaling downstream of endosomal TLRs, increased humoral responses to nucleic acid-containing antigens, and the propensity toward humoral autoimmunity. Mechanistically, TLR-dependent NOX2 activation promotes LC3-mediated maturation of TLR-containing endosomes, resulting in signal termination. CRISPR-mediated disruption of NCF1 confirmed a direct role for NOX2 in regulating endosomal TLR signaling in primary human B cells. Together, these data highlight a new B cell-specific mechanism contributing to autoimmune risk in NCF1 and NCF2 variant carriers.

Whitening of brown adipose tissue inhibits osteogenic differentiation via secretion of S100A8/A9

The mechanism by which brown adipose tissue (BAT) regulates bone metabolism is unclear. Here, we reveal that BAT secretes S100A8/A9, a previously unidentified BAT adipokine (batokine), to impair bone formation. Brown adipocytes-specific knockout of Rheb (RhebBAD KO), the upstream activator of mTOR, causes BAT malfunction to inhibit osteogenesis. Rheb depletion induces NF-κB dependent S100A8/A9 secretion from brown adipocytes, but not from macrophages. In wild-type mice, age-related Rheb downregulation in BAT is associated with enhanced S100A8/A9 secretion. Either batokines from RhebBAD KO mice, or recombinant S100A8/A9, inhibits osteoblast differentiation of mesenchymal stem cells in vitro by targeting toll-like receptor 4 on their surfaces. Conversely, S100A8/A9 neutralization not only rescues the osteogenesis repressed in the RhebBAD KO mice, but also alleviates age-related osteoporosis in wild-type mice. Collectively, our data revealed an unexpected BAT-bone crosstalk driven by Rheb-S100A8/A9, uncovering S100A8/A9 as a promising target for the treatment, and potentially, prevention of osteoporosis.

Cyclical palmitoylation regulates TLR9 signalling and systemic autoimmunity in mice

Toll-like receptor 9 (TLR9) recognizes self-DNA and plays intricate roles in systemic lupus erythematosus (SLE). However, the molecular mechanism regulating the endosomal TLR9 response is incompletely understood. Here, we report that palmitoyl-protein thioesterase 1 (PPT1) regulates systemic autoimmunity by removing S-palmitoylation from TLR9 in lysosomes. PPT1 promotes the secretion of IFNα by plasmacytoid dendritic cells (pDCs) and TNF by macrophages. Genetic deficiency in or chemical inhibition of PPT1 reduces anti-nuclear antibody levels and attenuates nephritis in B6.Sle1yaa mice. In healthy volunteers and patients with SLE, the PPT1 inhibitor, HDSF, reduces IFNα production ex vivo. Mechanistically, biochemical and mass spectrometry analyses demonstrated that TLR9 is S-palmitoylated at C258 and C265. Moreover, the protein acyltransferase, DHHC3, palmitoylates TLR9 in the Golgi, and regulates TLR9 trafficking to endosomes. Subsequent depalmitoylation by PPT1 facilitates the release of TLR9 from UNC93B1. Our results reveal a posttranslational modification cycle that controls TLR9 response and autoimmunity.

From immunology to artificial intelligence: revolutionizing latent tuberculosis infection diagnosis with machine learning

Latent tuberculosis infection (LTBI) has become a major source of active tuberculosis (ATB). Although the tuberculin skin test and interferon-gamma release assay can be used to diagnose LTBI, these methods can only differentiate infected individuals from healthy ones but cannot discriminate between LTBI and ATB. Thus, the diagnosis of LTBI faces many challenges, such as the lack of effective biomarkers from Mycobacterium tuberculosis (MTB) for distinguishing LTBI, the low diagnostic efficacy of biomarkers derived from the human host, and the absence of a gold standard to differentiate between LTBI and ATB. Sputum culture, as the gold standard for diagnosing tuberculosis, is time-consuming and cannot distinguish between ATB and LTBI. In this article, we review the pathogenesis of MTB and the immune mechanisms of the host in LTBI, including the innate and adaptive immune responses, multiple immune evasion mechanisms of MTB, and epigenetic regulation. Based on this knowledge, we summarize the current status and challenges in diagnosing LTBI and present the application of machine learning (ML) in LTBI diagnosis, as well as the advantages and limitations of ML in this context. Finally, we discuss the future development directions of ML applied to LTBI diagnosis.

Unlocking the Complex Cell Biology of Coral-Dinoflagellate Symbiosis: A Model Systems Approach

Symbiotic interactions occur in all domains of life, providing organisms with resources to adapt to new habitats. A prime example is the endosymbiosis between corals and photosynthetic dinoflagellates. Eukaryotic dinoflagellate symbionts reside inside coral cells and transfer essential nutrients to their hosts, driving the productivity of the most biodiverse marine ecosystem. Recent advances in molecular and genomic characterization have revealed symbiosis-specific genes and mechanisms shared among symbiotic cnidarians. In this review, we focus on the cellular and molecular processes that underpin the interaction between symbiont and host. We discuss symbiont acquisition via phagocytosis, modulation of host innate immunity, symbiont integration into host cell metabolism, and nutrient exchange as a fundamental aspect of stable symbiotic associations. We emphasize the importance of using model systems to dissect the cellular complexity of endosymbiosis, which ultimately serves as the basis for understanding its ecology and capacity to adapt in the face of climate change.

M2a macrophages facilitate resolution of chemically-induced colitis in TLR4-SNP mice

IMPORTANCE

Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, impacts millions of individuals worldwide and severely impairs the quality of life for patients. Dysregulation of innate immune signaling pathways reduces barrier function and exacerbates disease progression. Macrophage (Mφ) signaling pathways are potential targets for IBD therapies. While multiple treatments are available for IBD, (i) not all patients respond, (ii) responses may diminish over time, and (iii) treatments often have undesirable side effects. Genetic studies have shown that the inheritance of two co-segregating SNPs expressed in the innate immune receptor, TLR4, is associated with human IBD. Mice expressing homologous SNPs ("TLR4-SNP" mice) exhibited more severe colitis than WT mice in a DSS-induced colonic inflammation/repair model. We identified a critical role for M2a "tissue repair" Mφ in the resolution of colitis. Our findings provide insight into potential development of novel therapies targeting Mφ signaling pathways that aim to alleviate the debilitating symptoms experienced by individuals with IBD.

Epstein-Barr virus infection: the micro and macro worlds

Epstein‒Barr virus (EBV) is a DNA virus that belongs to the human B lymphotropic herpesvirus family and is highly prevalent in the human population. Once infected, a host can experience latent infection because EBV evades the immune system, leading to hosts harboring the virus for their lifetime. EBV is associated with many diseases and causes significant challenges to human health. This review first offers a description of the natural history of EBV infection, clarifies the interaction between EBV and the immune system, and finally focuses on several major types of diseases caused by EBV infection.

Yacon (Smallanthus sonchifolius) and kefir improved intestinal and bone health but without symbiotic benefits in rats

Kefir is a natural source of probiotics, and yacon (Smallanthus sonchifolius) is a tuberous root rich in fructooligosaccharides, with prebiotic properties. We hypothesized that kefir and yacon can improve bone and intestinal health and that their synbiotic effects will enhance these benefits. The properties of yacon and kefir and their association were evaluated in the intestinal and bone health in rats. Forty Wistar male rats were divided into 4 groups (n = 10): control (C), kefir (K), yacon (Y), and yacon + kefir (YK) and received an AIN-93 M diet containing 50% of the daily recommendation of calcium for 42 days. Group K received 1 mL/day of kefir containing 10⁸ CFU/mL; group Y received yacon flour (5% fructooligosaccharides); and the YK group received the same treatment as the Y and K groups. Urine and feces were collected to determine the calcium balance. Serum biomarkers of bone formation and resorption, osteocalcin, N telopeptides of collagen type I and C-telopeptide of collagen type I, intraluminal pH, intestinal permeability, and secretory immunoglobulin A were evaluated. Yacon reduced intraluminal pH alone or in association with kefir (groups Y and YK). Yacon also improved intestinal permeability (lowered lactulose and mannitol excretion) and increased calcium balance and osteocalcin, a biomarker of bone formation. In turn, K improved immunity by increasing secretory immunoglobulin A secretion and reducing bone resorption biomarkers (C-telopeptide of collagen type I and N telopeptides of collagen type I). Thus, yacon and kefir had beneficial effects on intestinal and bone health; however, the association between them did not demonstrate a synbiotic effect.

TLR7 promotes skin inflammation via activating NFκB-mTORC1 axis in rosacea

Rosacea is a chronic inflammatory skin disease originated from damaged skin barrier and innate/adaptive immune dysregulation. Toll-like receptors (TLRs) sense injured skin and initiate downstream inflammatory and immune responses, whose role in rosacea is not fully understood. Here, via RNA-sequencing analysis, we found that the TLR signaling pathway is the top-ranked signaling pathway enriched in rosacea skin lesions, in which TLR7 is highlighted and positively correlated with the inflammation severity of disease. In LL37-induced rosacea-like mouse models, silencing TLR7 prevented the development of rosacea-like skin inflammation. Specifically, we demonstrated that overexpressing TLR7 in keratinocytes stimulates rapamycin-sensitive mTOR complex 1 (mTORC1) pathway via NFκB signaling. Ultimately, TLR7/NFκ B/mTORC1 axis promotes the production of cytokines and chemokines, leading to the migration of CD4+T cells, which are infiltrated in the lesional skin of rosacea. Our report reveals the crucial role of TLR7 in rosacea pathogenesis and indicatesa promising candidate for rosacea treatments.

Mitochondrial Damage-Associated Molecular Patterns and Metabolism in the Regulation of Innate Immunity

The innate immune system, as the host's first line of defense against intruders, plays a critical role in recognizing, identifying, and reacting to a wide range of microbial intruders. There is increasing evidence that mitochondrial stress is a major initiator of innate immune responses. When mitochondria's integrity is disrupted or dysfunction occurs, the mitochondria's contents are released into the cytosol. These contents, like reactive oxygen species, mitochondrial DNA, and double-stranded RNA, among others, act as damage-related molecular patterns (DAMPs) that can bind to multiple innate immune sensors, particularly pattern recognition receptors, thereby leading to inflammation. To avoid the production of DAMPs, in addition to safeguarding organelles integrity and functionality, mitochondria may activate mitophagy or apoptosis. Moreover, mitochondrial components and specific metabolic regulations modify properties of innate immune cells. These include macrophages, dendritic cells, innate lymphoid cells, and so on, in steady state or in stimulation that are involved in processes ranging from the tricarboxylic acid cycle to oxidative phosphorylation and fatty acid metabolism. Here we provide a brief summary of mitochondrial DAMPs' initiated and potentiated inflammatory response in the innate immune system. We also provide insights into how the state of activation, differentiation, and functional polarization of innate immune cells can be influenced by alteration to the metabolic pathways in mitochondria.

TRAF3 deficiency in MDCK cells improved sensitivity to the influenza A virus

Tumor necrosis factor receptor-associated factor 3 (TRAF3), an adaptor protein, has significant and varying effects on immunity depending on cell types. The role of TRAF3 in Madin-Darby Canine Kidney Epithelial (MDCK) cell resistance to influenza A virus (IVA) remains elusive. In the present study, CRISPR-Cas9 gene editing technology was used to construct the TRAF3 knockout MDCK cells (MDCK-TRAF3-/-). Hemagglutination assay, plaque assay, transcriptome, and quantitative real-time PCR were performed after IVA infection. The results showed that after IVA infection, HA titers and virus titers were promoted, interferon I-related pathways were significantly blocked, and transcription of several antiviral-related genes was significantly decreased in MDCK-TRAF3-/- cells. Thus, our study suggests that TRAF3 gene knockout reduced MDCK cell's resistance to IVA, thereby resulting in a promising way for IVA isolation and vaccine manufacturing.

Regionalization of the antiviral response in the gastrointestinal tract to provide spatially controlled host/pathogen interactions

As the largest mucosal surface, the gastrointestinal (GI) tract plays a key role in protecting the host against pathogen infections. It is a first line of defense against enteric viruses and must act to control infection while remaining tolerant to the high commensal bacteria load found within the GI tract. The GI tract can be divided into six main sections (stomach, duodenum, jejunum, ileum, colon, and rectum), and enteric pathogens have evolved to infect distinct parts of the GI tract. The intestinal epithelial cells (IECs) lining the GI tract are immune competent and can counteract these infections through their intrinsic immune response. Type I and type III interferons (IFNs) are antiviral cytokines that play a key role in protecting IECs against viruses with the type III IFN being the most important. Recent work has shown that IECs derived from the different sections of the GI tract display a unique expression of pattern recognition receptors used to fight pathogen infections. Additionally, it was also shown that these cells show a section-specific response to enteric viruses. This mini-review will discuss the molecular strategies used by IECs to detect and combat enteric viruses highlighting the differences existing along the entero-caudal axis of the GI tract. We will provide a perspective on how these spatially controlled mechanisms may influence virus tropism and discuss how the intestinal micro-environment may further shape the response of IECs to virus infections.

Physicochemical characterization of biological and synthetic forms of two lipid A-based TLR4 agonists

Toll-like receptor (TLR) agonists are recognized as potential immune-enhancing adjuvants and are included in several licensed vaccines. Monophosphoryl lipid A (MPL®, GlaxoSmithKline) is one such TLR4 agonist that has been approved for use in human vaccines, such as Cervarix and Shingrix. Due to the heterogeneous nature of biologically derived MPL and the need for safer and more potent adjuvants, our groups have developed the novel TLR4 agonist candidates, BECC438 and BECC470 using the Bacterial Enzymatic Combinatorial Chemistry (BECC) platform. BECC438 and BECC470 have been included in studies to test their adjuvant potential and found to be effective in vaccines against both viral and bacterial disease agents. Here, we report detailed biophysical characterization of BECC438 and BECC470 purified from a biological source (BECC438b and BECC470b, respectively) and synthesized chemically (BECC438s and BECC470s, respectively). Both BECC438s and BECC470s have identical acyl chain configurations, BECC438s is bis-phosphorylated and BECC470s is mono-phosphorylated with the removal of the 4' phosphate moiety. We determined the phase transition temperatures for the acyl chains of BECC438b and BECC470b and found them to be different from those exhibited by their synthetic counterparts. Furthermore, the phosphate groups of BECC438b and BECC470b are more highly hydrated than are those of BECC438s and BECC470s. In addition to exploring the BECC molecules' biophysical features in aqueous solution, we explored potential formulation of BECC438 and BECC470 with the aluminum-based adjuvant Alhydrogel and as part of an oil-in-water emulsion (Medimmune Emulsion or ME). All of the lipid A analogues could be fully absorbed to Alhydrogel or incorporated onto ME. Surprisingly, the BECC470s molecule, unlike the others, displayed a nearly baseline signal when monitored using a Limulus amebocyte lysate (LAL) endotoxin detection system. Despite this, it was shown to behave as an agonist for human and mouse TLR4 when tested using multiple cell-based systems. This work paves the way for further formulation optimization of two chemically defined TLR4 agonists that are showing great promise as vaccine adjuvants.

Cbf-14, a cationic peptide derived from cathelin-domain, exhibits anti-inflammation activity via inhibiting PI3K- Akt /ROS/ NF-κB signaling pathway

Cbf-14 with the sequence RLLRKFFRKLKKSV, is an effective antimicrobial peptide derived from a cathelin-like domain. Previous reports have demonstrated that Cbf-14 not only exerts antimicrobial activity against penicillin-resistant bacteria but also alleviates bacterial-induced inflammation in E. coli BL21 (DE3)-NDM-1-infected mice. In this article, we demonstrated that Cbf-14 can effectively reduce RAW 264.7 intracellular infection caused by clinical strain E. coli and alleviate the inflammatory response of cells and improve cell survival after infection. Therefore, we established the LPS-stimulated RAW 264.7 cell inflammation model to uncover the molecular mechanisms of the peptide Cbf-14 in anti-inflammatory activity. The results reveal that Cbf-14 can decrease LPS-induced ROS secretion by blocking the membrane translocation of p47-phox subunits and suppressing p47-phox protein phosphorylation. Meanwhile, this peptide can down-regulate the over-expression of iNOS, and finally inhibit the NO excessive secretion from RAW 264.7 macrophages stimulated by LPS. Moreover, Cbf-14 also down-regulates the expression levels of p-IκB and p-p65 and inhibits the nuclear translocation of NF-κB through blocking MAPK- and/or PI3K-Akt signaling pathways. Overall, Cbf-14 exhibits anti-inflammatory activity through inhibiting NF-κB activity and ROS production via PI3K- Akt signaling pathway.

Inulin-type fructans obtained from Atractylodis Macrocephalae by water/alkali extraction and immunoregulatory evaluation

Two homogenous polysaccharides extracted from Atractylodes macrocephala Koidz. were investigated by water extraction (AMP-F_W) and alkali solution extraction (AMP-F_A) after purification by anion exchange column and size exclusion chromatography. The molecular weight of AMP-F_W and AMP-F_A were 2874 Da and 3438 Da, respectively, estimated by high performance gel permeation chromatography (HPGPC). The monosaccharide compositions of AMP-F_W and AMP-F_A were glucose and fructose at a molar ratio of 0.11:0.89 determined by high performance anion exchange chromatography (HPAEC). The functional groups, glycosidic linkages and the chemical structure were characterized by FT-IR, GC-MS and NMR, which comprehensively indicated a similar inulin-type fructan structure of the two polysaccharides from A. macrocephala. However, the scanning electron microscopy (SEM) results showed different microstructures that irregular lamellar shape for the AMP-F_W and spheroid shape for the AMP-F_A. The further studies on immunomodulation showed that AMP-F_W at 50 μg/mL could significantly (P < 0.05) stimulate RAW 264.7 cells by enhancing the mRNA expression of TNF-α and IL-1β, which had a relative high immunomodulatory potential when compared to AMP-F_A. Their activation on different toll-like receptors (TLR) also indicated their different roles in the immunoregulation. Overall, these findings reported here will serve as the basis for further structure-activity relationship studies.

Association of circulating MtDNA with CVD in hemodialysis patients and in vitro effect of exogenous MtDNA on cardiac microvascular inflammation

BACKGROUND

Chronic kidney disease (CKD) patients sustain a fairly high prevalence of cardiovascular disease (CVD). Microvascular inflammation is an early manifestation of CVD, and the released mitochondrial DNA (MtDNA) has been proposed to be a crucial integrator of inflammatory signals. Herein, the aim of this study was to determine the relationship between CVD, microvessel, and circulating MtDNA in the settings of uremia.

METHODS

Forty-two maintenance hemodialysis (MHD) patients and 36 health controls were enrolled in this study. Plasma cell-free MtDNA was detected by TaqMan-based qPCR assay. CVD risk markers including high-sensitive C-reactive protein (Hs-CRP), monocyte chemoattractant protein-1 (MCP-1), fibrinogen, and erythrocyte sedimentation rate (ESR) were measured by standard assays. Ten-year CVD risk was calculated from the Framingham risk score (FRS) model. In vitro study, human cardiac microvascular endothelial cells (HCMECs) were incubated with normal or uremic serum, with or without exogenous MtDNA. Intracellular toll-like receptor 9 (TLR9), adhesion molecule 1 (ICAM-1), MCP-1 and tumor necrosis factor-α (TNF-α) and cytosolic MtDNA were detected by qPCR.

RESULTS

Plasma MtDNA in MHD patients was significantly higher than healthy controls (4.74 vs. 2.41 × 10⁵ copies/mL; p = 0.000). Subsequently, the MHD patients were classified into two groups based on the MtDNA median (4.34 × 10⁵ copies/mL). In stratified analyses, the levels of Hs-CRP (5.02 vs. 3.73 mg/L; p = 0.042) and MCP-l (99.97 vs. 64.72 pg/mL; p = 0.008) and FRS (21.80 vs. 16.52; p = 0.016) in the high plasma MtDNA group were higher than those in the low plasma MtDNA group. In vitro study, we found that exogenous MtDNA aggravated uremic serum-induced microvascular inflammation (ICAM-1 and TNF-α) in HCMECs (all p < 0.05). Besides, the addition of MtDNA to the medium resulted in a further increase in cytosolic MtDNA and TLR9 levels in uremic serum-treated cells (all p < 0.05). In patients with MHD, MtDNA levels in plasma were significantly reduced after a single routine hemodialysis (pre 4.47 vs. post 3.45 × 10⁵ copies/mL; p = 0.001) or hemodiafiltration (pre 4.85 vs. post 4.09 × 10⁵ copies/mL; p = 0.001). These two approaches seem similar in terms of MtDNA clearance rate (21.26% vs. 11.94%; p = 0.172).

CONCLUSIONS

Overall, the present study suggests that MtDNA released into the circulation under the uremic toxin environment may adversely affect the cardiovascular system by exacerbating microvascular inflammation, and that reducing circulating MtDNA might be a future therapeutic strategy for the prevention of MHD-related CVD.

Is it possible to intervene early cirrhosis by targeting toll-like receptors to rebalance the intestinal microbiome?

Cirrhosis is a progressive chronic liver disease caused by one or more causes and characterized by diffuse fibrosis, pseudolobules, and regenerated nodules. Once progression to hepatic decompensation, the function of the liver and other organs is impaired and almost impossible to reverse and recover, which often results in hospitalization, impaired quality of life, and high mortality. However, in the early stage of cirrhosis, there seems to be a possibility of cirrhosis reversal. The development of cirrhosis is related to the intestinal microbiota and activation of toll-like receptors (TLRs) pathways, which could regulate cell proliferation, apoptosis, expression of the hepatomitogen epiregulin, and liver inflammation. Targeting regulation of intestinal microbiota and TLRs pathways could affect the occurrence and development of cirrhosis and its complications. In this paper, we first reviewed the dynamic change of intestinal microbiota and TLRs during cirrhosis progression. And further discussed the interaction between them and potential therapeutic targets to reverse early staged cirrhosis.

Network pharmacology- and molecular simulation-based exploration of therapeutic targets and mechanisms of heparin for the treatment of sepsis/COVID-19

Critically infected patients with COVID-19 (coronavirus disease 2019) are prone to develop sepsis-related coagulopathy as a result of a robust immune response. The mechanism underlying the relationship between sepsis and COVID-19 is largely unknown. LMWH (low molecular weight heparin) exhibits both anti-inflammatory and anti-coagulating properties that result in a better prognosis of severely ill patients with COVID-19 co-associated with sepsis-induced coagulopathy or with a higher D-dimer value. Heparin-associated molecular targets and their mechanism of action in sepsis/COVID-19 are not well understood. In this work, we characterize the pharmacological targets, biological functions and therapeutic actions of heparin in sepsis/COVID-19 from the perspective of network pharmacology. A total of 38 potential targets for heparin action against sepsis/COVID-19 and 8 core pharmacological targets were identified, including IL6, KNG1, CXCL8, ALB, VEGFA, F2, IL10 and TNF. Moreover, enrichment analysis showed that heparin could help in treating sepsis/COVID-19 through immunomodulation, inhibition of the inflammatory response, regulation of angiogenesis and antiviral activity. The pharmacological effects of heparin against these targets were further confirmed by molecular docking and simulation analysis, suggesting that heparin exerts effective binding capacity by targeting the essential residues in sepsis/COVID-19. Prospective clinical practice evaluations may consider the use of these key prognostic indicators for the treatment of sepsis/COVID-19.Communicated by Ramaswamy H. Sarma.

Interaction between nanomaterials and the innate immune system across evolution

Interaction of engineered nanomaterials (ENMs) with the immune system mainly occurs with cells and molecules of innate immunity, which are present in interface tissues of living organisms. Immuno-nanotoxicological studies aim at understanding if and when such interaction is inconsequential or may cause irreparable damage. Since innate immunity is the first line of immune reactivity towards exogenous agents and is highly conserved throughout evolution, this review focuses on the major effector cells of innate immunity, the phagocytes, and their major sensing receptors, Toll-like receptors (TLRs), for assessing the modes of successful versus pathological interaction between ENMs and host defences. By comparing the phagocyte- and TLR-dependent responses to ENMs in plants, molluscs, annelids, crustaceans, echinoderms and mammals, we aim to highlight common recognition and elimination mechanisms and the general sufficiency of innate immunity for maintaining tissue integrity and homeostasis.

Examining the Kinetics of Phagocytosis-Coupled Inflammasome Activation in Murine Bone Marrow-Derived Dendritic Cells

In the present chapter, we describe procedures to assess NLRP3 and NLRC4 inflammasome assembly by immunofluorescence microscopy or live cell imaging, together with inflammasome activation by biochemical and immunological techniques upon phagocytosis. We also include a step-by-step guide to automating the counting of inflammasome "specks" after imaging. While our focus resides on murine bone marrow-derived dendritic cells differentiated in the presence of granulocyte-macrophage colony-stimulating factor, which results in a cell population that resembles inflammatory dendritic cells, the strategies described herein may apply to other phagocytes as well.

Non-coding RNAs targeting NF-κB pathways in aquatic animals: A review

Nuclear factor-kappa B (NF-κB) pathways have a close relationship with many diseases, especially in terms of the regulation of inflammation and the immune response. Non-coding RNAs (ncRNAs) are a heterogeneous subset of endogenous RNAs that directly affect cellular function in the absence of proteins or peptide products; these include microRNAs (miRNAs), long noncoding RNAs (lncRNAs), circular RNAs (circRNAs), etc. Studies on the roles of ncRNAs in targeting the NF-κB pathways in aquatic animals are scarce. A few research studies have confirmed detailed regulatory mechanisms among ncRNAs and the NF-κB pathways in aquatic animals. This comprehensive review is presented concerning ncRNAs targeting the NF-κB pathway in aquatic animals and provides new insights into NF-κB pathways regulatory mechanisms of aquatic animals. The review discusses new possibilities for developing non-coding-RNA-based antiviral applications in fisheries.

Classification of Extracellular Vesicles Based on Surface Glycan Structures by Spongy-like Separation Media

Extracellular vesicles (EVs) are lipid bilayer vesicles that enclose various biomolecules. EVs hold promise as sensitive biomarkers to detect and monitor various diseases. However, they have heterogeneous molecular compositions. The compositions of EVs from identical donor cells obtained using the same purification methods may differ, which is a significant obstacle for elucidating objective biological functions. Herein, the potential of a novel lectin-based affinity chromatography (LAC) method to classify EVs based on their glycan structures is demonstrated. The proposed method utilizes a spongy-like monolithic polymer (spongy monolith, SPM), which consists of poly(ethylene-co-glycidyl methacrylate) with continuous micropores and allows an efficient in situ protein reaction with epoxy groups. Two distinct lectins with different specificities, Sambucus sieboldiana agglutinin and concanavalin A, are effectively immobilized on SPM without impacting the binding activity. Moreover, high recovery rates of liposomal nanoparticles as a model of EVs are achieved due to the large flow-through pores (>10 μm) of SPM compared to a typical agarose gel. Finally, lectin-immobilized SPMs are employed to classify EVs based on the surface glycan structures and demonstrate different subpopulations by proteome profiling. This is the first approach to clarify the variation of protein contents in EVs by the difference of surface glycans via lectin immobilized media.

An AP-3-dependent pathway directs phagosome fusion with Rab8 and Rab11 vesicles involved in TLR2 signaling

Intracellular compartmentalization of ligands, receptors and signaling molecules has been recognized as an important regulator of inflammation. The toll-like receptor (TLR) 2 pathway utilizes the trafficking molecule adaptor protein 3 (AP-3) to activate interleukin (IL)-6 signaling from within phagosomal compartments. To better understand the vesicular pathways that may contribute to intracellular signaling and cooperate with AP-3, we performed a vesicular siRNA screen. We identified Rab8 and Rab11 GTPases as important in IL-6 induction upon stimulation with the TLR2 ligand Pam3 CSK4 or the pathogen, Borrelia burgdorferi (Bb), the causative agent of Lyme disease. These Rabs were recruited to late and lysosomal stage phagosomes and co-transported with TLR2 signaling adaptors and effectors, such as MyD88, TRAM and TAK1, in an AP-3-dependent manner. Our data support a model where AP-3 mediates the recruitment of recycling and secretory vesicles and the assembly of signaling complexes at the phagosome.

Effect of Toll-like receptor-2, -4, -5, -7, and NOD2 stimulation on potassium channel conductance in intestinal epithelial cells

Disproportionate activation of pattern recognition receptors plays a role in inflammatory bowel disease (IBD) pathophysiology. Diarrhea is a hallmark symptom of IBD, resulting at least in part from an electrolyte imbalance that may be caused by changes in potassium channel activity. We evaluated the impact of Toll-like receptors (TLRs) and nucleotide-binding oligomerization domain 2 (NOD2) stimulation on potassium conductance of the basolateral membrane in human intestinal epithelial cells (IECs) and the role of potassium channels through electrophysiological assays under short-circuit current in Ussing chambers. TLRs and NOD2 were stimulated using specific agonists, and potassium channels were selectively blocked using triarylmethane-34 (TRAM-34), adenylyl-imidodiphosphate (AMP-PNP), and BaCl₂. Potassium conductance of the basolateral membrane decreased upon activation of TLR2, TLR4, and TLR7 in T84 cells (means ± SE, -11.2 ± 4.5, -40.4 ± 7.2, and -19.4 ± 5.9, respectively) and in Caco-2 cells (-13.1 ± 5.7, -55.7 ± 7.4, and -29.1 ± 7.2, respectively). In contrast, activation of TLR5 and NOD2 increased basolateral potassium conductance, both in T84 cells (18.0 ± 4.1 and 18.4 ± 2.8, respectively) and in Caco-2 cells (21.2 ± 8.4 and 16.0 ± 3.6, respectively). TRAM-34 and AMP-PNP induced a decrease in basolateral potassium conductance upon TLR4 stimulation in both cell lines. Both K_Ca3.1- and K_ir6-channels appear to be important mediators of this effect in IECs and could be potential targets for therapeutic agent development.NEW & NOTEWORTHY This study highlights that PRRs stimulation directly influences K⁺-channel conductance in IECs. TLR-2, -4, -7 stimulation decreased K⁺ conductance, whereas TLR5 and NOD2 stimulation had the opposite effect, leading to an increase of it instead. This study reports for the first time that K_Ca3.1- and K_ir6-channels play a role in K⁺ transport pathways triggered by TLR4 stimulation. These findings suggest that K_Ca3.1- and K_ir6-channels modulation may be a potential target for new therapeutic agents in IBD.

TLR9 Negatively Regulates Intracellular Bacterial Killing by Pyroptosis in Burkholderia pseudomallei-Infected Mouse Macrophage Cell Line (Raw264.7)

Melioidosis is a serious infectious disease caused by Burkholderia pseudomallei. This bacterium is able to survive and multiply inside the immune cells such as macrophages. It is well established that Toll-like receptors (TLRs), particularly surface TLRs such as TLR2, TLR4, and TLR5, play an essential role in defending against this bacterial infection. However, the involvement of endosomal TLRs in the infection has not been elucidated. In this study, we demonstrated that the number of intracellular bacteria is reduced in TLR9-depleted RAW264.7 cells infected with B. pseudomallei, suggesting that TLR9 is involved in intracellular bacterial killing in macrophages. As several reports have previously demonstrated that pyroptosis is essential for restricting intracellular bacterial killing, particularly in B. pseudomallei infection, we also observed an increased release of cytosolic enzyme lactate dehydrogenase (LDH) in TLR9-depleted cells infected with B. pseudomallei, suggesting TLR9 involvement in pyroptosis in this context. Consistently, the increases in caspase-11 and gasdermind D (GSDMD) activations, which are responsible for the LDH release, were also detected. Moreover, we demonstrated that the increases in pyroptosis and bacterial killing in B. pseudomallei-infected TLR9-depleted cells were due to the augmentation of the IFN-β, one of the key cytokines known to regulate caspase-11. Altogether, this finding showed that TLR9 suppresses macrophage killing of B. pseudomallei by regulating pyroptosis. This information provides a novel mechanism of TLR9 in the regulation of intracellular bacterial killing by macrophages, which could potentially be leveraged for therapeutic intervention. IMPORTANCE Surface TLRs have been well established to play an essential role in Burkholderia pseudomallei infection. However, the role of endosomal TLRs has not been elucidated. In the present study, we demonstrated that TLR9 plays a crucial role by negatively regulating cytokine production, particularly IFN-β, a vital cytokine to control pyroptosis via caspase-11 activation. By depletion of TLR9, the percentage of pyroptosis was significantly increased, leading to suppression of intracellular survival in B. pseudomallei-infected macrophages. These findings provide a new role of TLR9 in macrophages.

Toll-like Receptor Mediation in SARS-CoV-2: A Therapeutic Approach

The innate immune system facilitates defense mechanisms against pathogen invasion and cell damage. Toll-like receptors (TLRs) assist in the activation of the innate immune system by binding to pathogenic ligands. This leads to the generation of intracellular signaling cascades including the biosynthesis of molecular mediators. TLRs on cell membranes are adept at recognizing viral components. Viruses can modulate the innate immune response with the help of proteins and RNAs that downregulate or upregulate the expression of various TLRs. In the case of COVID-19, molecular modulators such as type 1 interferons interfere with signaling pathways in the host cells, leading to an inflammatory response. Coronaviruses are responsible for an enhanced immune signature of inflammatory chemokines and cytokines. TLRs have been employed as therapeutic agents in viral infections as numerous antiviral Food and Drug Administration-approved drugs are TLR agonists. This review highlights the therapeutic approaches associated with SARS-CoV-2 and the TLRs involved in COVID-19 infection.

Polyphenols–Gut–Heart: An Impactful Relationship to Improve Cardiovascular Diseases

A healthy gut provides the perfect habitat for trillions of bacteria, called the intestinal microbiota, which is greatly responsive to the long-term diet; it exists in a symbiotic relationship with the host and provides circulating metabolites, hormones, and cytokines necessary for human metabolism. The gut–heart axis is a novel emerging concept based on the accumulating evidence that a perturbed gut microbiota, called dysbiosis, plays a role as a risk factor in the pathogenesis of cardiovascular disease. Consequently, recovery of the gut microbiota composition and function could represent a potential new avenue for improving patient outcomes. Despite their low absorption, preclinical evidence indicates that polyphenols and their metabolites are transformed by intestinal bacteria and halt detrimental microbes’ colonization in the host. Moreover, their metabolites are potentially effective in human health due to antioxidant, anti-inflammatory, and anti-cancer effects. The aim of this review is to provide an overview of the causal role of gut dysbiosis in the pathogenesis of atherosclerosis, hypertension, and heart failure; to discuss the beneficial effects of polyphenols on the intestinal microbiota, and to hypothesize polyphenols or their derivatives as an opportunity to prevent and treat cardiovascular diseases by shaping gut eubiosis.

Toll-Like Receptor 3 in Cardiovascular Diseases

Toll-like receptor 3 (TLR3) is an important member of the innate immune response receptor toll-like receptors (TLRs) family, which plays a vital role in regulating immune response, promoting the maturation and differentiation of immune cells, and participating in the response of pro-inflammatory factors. TLR3 is activated by pathogen-associated molecular patterns and damage-associated molecular patterns, which support the pathophysiology of many diseases related to inflammation. An increasing number of studies have confirmed that TLR3, as a crucial medium of innate immunity, participates in the occurrence and development of cardiovascular diseases (CVDs) by regulating the transcription and translation of various cytokines, thus affecting the structure and physiological function of resident cells in the cardiovascular system, including vascular endothelial cells, vascular smooth muscle cells, cardiomyocytes, fibroblasts and macrophages. The dysfunction and structural damage of vascular endothelial cells and proliferation of vascular smooth muscle cells are the key factors in the occurrence of vascular diseases such as pulmonary arterial hypertension, atherosclerosis, myocardial hypertrophy, myocardial infarction, ischaemia/reperfusion injury, and heart failure. Meanwhile, cardiomyocytes, fibroblasts, and macrophages are involved in the development of CVDs. Therefore, the purpose of this review was to explore the latest research published on TLR3 in CVDs and discuss current understanding of potential mechanisms by which TLR3 contributes to CVDs. Even though TLR3 is a developing area, it has strong treatment potential as an immunomodulator and deserves further study for clinical translation.

Nucleic Acid Sensing by Toll-Like Receptors in the Endosomal Compartment

Toll-like receptors (TLRs) respond to pathogen constituents, such as microbial lipids and nucleic acids (NAs). TLRs recognize NAs in endosomal compartments. Structural and functional studies have shown that recognition of NAs by TLRs depends on NA processing by RNases and DNases. DNase II-dependent DNA degradation is required for TLR9 responses to single-stranded DNAs, whereas RNase T2-dependent RNA degradation enables TLR7 and TLR8 to respond to nucleosides and oligoribonucleotides. In contrast, RNases and DNases negatively regulate TLR responses by degrading their ligands. RNase T2 negatively regulates TLR3 responses to degrading the TLR3 ligand double-stranded RNAs. Therefore, NA metabolism in the endosomal compartments affects the endosomal TLR responses. Dysregulation of NA metabolism in the endosomal compartment drives the TLR-dependent pathologies in human diseases.

Role of high mobility group box protein 1 in depression: A mechanistic and therapeutic perspective

As a common and serious psychiatric disorder, depression significantly affects psychosocial functioning and quality of life. However, the mechanism of depression is still enigmatic and perplexing, which limits its precise and effective therapeutic methods. Recent studies demonstrated that neuroinflammation activation plays an important role in the pathophysiology of depression. In this respect, high mobility group box 1 (HMGB1) may be a possible signaling inducer of neuroinflammation and can be a potential mechanistic and therapeutic target for depression. Herein, we review recent studies on the mechanistic and therapeutic targets of HMGB1 in depression and propose potential perspectives on this topic.

Structure and function of non-digestible carbohydrates in the gut microbiome

Together with proteins and fats, carbohydrates are one of the macronutrients in the human diet. Digestible carbohydrates, such as starch, starch-based products, sucrose, lactose, glucose and some sugar alcohols and unusual (and fairly rare) α-linked glucans, directly provide us with energy while other carbohydrates including high molecular weight polysaccharides, mainly from plant cell walls, provide us with dietary fibre. Carbohydrates which are efficiently digested in the small intestine are not available in appreciable quantities to act as substrates for gut bacteria. Some oligo- and polysaccharides, many of which are also dietary fibres, are resistant to digestion in the small intestines and enter the colon where they provide substrates for the complex bacterial ecosystem that resides there. This review will focus on these non-digestible carbohydrates (NDC) and examine their impact on the gut microbiota and their physiological impact. Of particular focus will be the potential of non-digestible carbohydrates to act as prebiotics, but the review will also evaluate direct effects of NDC on human cells and systems.

Nucleic Acid Sensing Pathways in DNA Repair Targeted Cancer Therapy

The repair of DNA damage is a complex process, which helps to maintain genome fidelity, and the ability of cancer cells to repair therapeutically DNA damage induced by clinical treatments will affect the therapeutic efficacy. In the past decade, great success has been achieved by targeting the DNA repair network in tumors. Recent studies suggest that DNA damage impacts cellular innate and adaptive immune responses through nucleic acid-sensing pathways, which play essential roles in the efficacy of DNA repair targeted therapy. In this review, we summarize the current understanding of the molecular mechanism of innate immune response triggered by DNA damage through nucleic acid-sensing pathways, including DNA sensing via the cyclic GMP-AMP synthase (cGAS), Toll-like receptor 9 (TLR9), absent in melanoma 2 (AIM2), DNA-dependent protein kinase (DNA-PK), and Mre11-Rad50-Nbs1 complex (MRN) complex, and RNA sensing via the TLR3/7/8 and retinoic acid-inducible gene I (RIG-I)-like receptors (RLRs). Furthermore, we will focus on the recent developments in the impacts of nucleic acid-sensing pathways on the DNA damage response (DDR). Elucidating the DDR-immune response interplay will be critical to harness immunomodulatory effects to improve the efficacy of antitumor immunity therapeutic strategies and build future therapeutic approaches.

Innate Immune Response to Dengue Virus: Toll-like Receptors and Antiviral Response

Dengue is a mosquito-borne viral disease caused by the dengue virus (DENV1-4). The clinical manifestations range from asymptomatic to life-threatening dengue hemorrhagic fever (DHF) and/or Dengue Shock Syndrome (DSS). Viral and host factors are related to the clinical outcome of dengue, although the disease pathogenesis remains uncertain. The innate antiviral response to DENV is implemented by a variety of immune cells and inflammatory mediators. Blood monocytes, dendritic cells (DCs) and tissue macrophages are the main target cells of DENV infection. These cells recognize pathogen-associated molecular patterns (PAMPs) through pattern recognition receptors (PRRs). Pathogen recognition is a critical step in eliciting the innate immune response. Toll-like receptors (TLRs) are responsible for the innate recognition of pathogens and represent an essential component of the innate and adaptive immune response. Ten different TLRs are described in humans, which are expressed in many different immune cells. The engagement of TLRs with viral PAMPs triggers downstream signaling pathways leading to the production of inflammatory cytokines, interferons (IFNs) and other molecules essential for the prevention of viral replication. Here, we summarize the crucial TLRs’ roles in the antiviral innate immune response to DENV and their association with viral pathogenesis.

Current Advances in Aptamer-based Biomolecular Recognition and Biological Process Regulation

The interaction between biomolecules with their target ligands plays a great role in regulating biological functions. Aptamers are short oligonucleotide sequences that can specifically recognize target biomolecules via structural complementarity and thus regulate related biological functions. In the past ten years, aptamers have made great progress in target biomolecule recognition, becoming a powerful tool to regulate biological functions. At present, there are many reviews on aptamers applied in biomolecular recognition, but few reviews pay attention to aptamer-based regulation of biological functions. Here, we summarize the approaches to enhancing aptamer affinity and the advancements of aptamers in regulating enzymatic activity, cellular immunity and cellular behaviors. Furthermore, this review discusses the challenges and future perspectives of aptamers in target recognition and biological functions regulation, aiming to provide some promising ideas for future regulation of biomolecular functions in a complex biological environment.

Fish-specific Toll-like receptor 14 (TLR14) from Asian swamp eel (Monopterus albus) is involved in immune response to bacterial infection

Toll-like receptors (TLRs) are a class of pattern recognition receptors (PRRs) that play a critical role in innate immune responses against pathogens. In the present study, a fish-specific TLR14 was identified and characterized from Monopterus albus (named MaTLR14), which consisted of a 2658 bp open reading frame encoding a protein of 885 amino acids. Phylogenetic analysis revealed that MaTLR14 belong to the TLR1 subfamily and shared the highest similarity to Paralichthys olivaceus TLR14. Immunohistochemistry assay showed that MaTLR14 mainly located in intestinal epithelial cells of hindgut. Immunofluorescence revealed that MaTLR14 largely localized to the intracellular region and partially co-localized with cell membrane of HeLa cells. The expression levels of MaTLR14 were upregulated in the liver, spleen, foregut and hindgut post infection with Aeromonas hydrophila. When stimulated with LPS and Flagellin, the MaTLR14 expression was elevated in isolated peripheral blood leukocytes. Further studies showed that recombinant MaTLR14-LRR could bind to both the gram-negative and gram-positive bacteria and cause agglutination. Subsequently, the signaling pathway of MaTLR14 was investigated. Confocal microscopy and co-immunoprecipitation assay demonstrated that MaTLR14 recruited MyD88 as adaptor. When overexpressed, MaTLR14 augmented the expression of TRAF6 and phosphorylation of ERK and p65, activated NF-κB and AP-1 and elicited the expression of il-6 and tnf-α. Collectively, MaTLR14 plays an important role in the microorganism recognition and signaling transduction.

The role of raftlin in the pathogenesis of chronic rhinosinusitis with nasal polyps

PURPOSE

The aim of this study was to investigate the possible role of raftlin (RFTN) in chronic rhinosinusitis with nasal polyps (CRSwNP). There is no study in the literature investigating the role of RFTN in the pathogenesis of CRSwNP.

METHODS

The present study was designed as a case-control study and conducted between 25.09.2020 and 01.01.2022. CRSwNP and control groups were formed in the study. Serum and tissue samples were taken from each patient in the study and their RFTN levels were measured. While nasal polyps were used for tissue samples in the CRSwNP group, middle meatus mucosa obtained during concha bullosa surgery was used in the control group.

RESULTS

The control group included 31 patients (8 female, 23 male) and the CRSwNP group included 49 patients (14 female, 35 male). The mean age of the control group was 40.42 ± 9.99 years, while the mean age of the CRSwNP group was 43.47 ± 10.19 years. When the groups are compared in terms of gender and age, there were no statistically significant differences (p = 0.78, p = 0.19, respectively). The serum RFTN levels in the control and CRSwNP groups were 7.85 ± 10.87 ng/ml, and 7.02 ± 8.59 ng/ml, respectively (p = 0.45). The tissue RFTN levels in the control group and CRSwNP group were 87.15 ± 69.91 ng/ml, and 66.50 ± 17.10 ng/ml, respectively (p = 0.04, statistically significant).

CONCLUSION

RFTN deficiency in nasal polyp tissue may be one of the reasons for the development of CRSwNP. Further studies are needed to elucidate the role of RFTN in CRSwNP.

Expression of the Immune Checkpoint Protein VISTA Is Differentially Regulated by the TGF-β1 - Smad3 Signaling Pathway in Rapidly Proliferating Human Cells and T Lymphocytes

Immune checkpoint proteins play crucial roles in human embryonic development but are also used by cancer cells to escape immune surveillance. These proteins and biochemical pathways associated with them form a complex machinery capable of blocking the ability of cytotoxic immune lymphoid cells to attack cancer cells and, ultimately, to fully suppress anti-tumor immunity. One of the more recently discovered immune checkpoint proteins is V-domain Ig-containing suppressor of T cell activation (VISTA), which plays a crucial role in anti-cancer immune evasion pathways. The biochemical mechanisms underlying regulation of VISTA expression remain unknown. Here, we report for the first time that VISTA expression is controlled by the transforming growth factor beta type 1 (TGF-β)-Smad3 signaling pathway. However, in T lymphocytes, we found that VISTA expression was differentially regulated by TGF-β depending on their immune profile. Taken together, our results demonstrate the differential biochemical control of VISTA expression in human T cells and various types of rapidly proliferating cells, including cancer cells, fetal cells and keratinocytes.

A Proximal-to-Distal Survey of Healthy Adult Human Small Intestine and Colon Epithelium by Single-Cell Transcriptomics

BACKGROUND & AIMS

Single-cell transcriptomics offer unprecedented resolution of tissue function at the cellular level, yet studies analyzing healthy adult human small intestine and colon are sparse. Here, we present single-cell transcriptomics covering the duodenum, jejunum, ileum, and ascending, transverse, and descending colon from 3 human beings.

METHODS

A total of 12,590 single epithelial cells from 3 independently processed organ donors were evaluated for organ-specific lineage biomarkers, differentially regulated genes, receptors, and drug targets. Analyses focused on intrinsic cell properties and their capacity for response to extrinsic signals along the gut axis across different human beings.

RESULTS

Cells were assigned to 25 epithelial lineage clusters. Multiple accepted intestinal stem cell markers do not specifically mark all human intestinal stem cells. Lysozyme expression is not unique to human Paneth cells, and Paneth cells lack expression of expected niche factors. Bestrophin 4 (BEST4)⁺ cells express Neuropeptide Y (NPY) and show maturational differences between the small intestine and colon. Tuft cells possess a broad ability to interact with the innate and adaptive immune systems through previously unreported receptors. Some classes of mucins, hormones, cell junctions, and nutrient absorption genes show unappreciated regional expression differences across lineages. The differential expression of receptors and drug targets across lineages show biological variation and the potential for variegated responses.

CONCLUSIONS

Our study identifies novel lineage marker genes, covers regional differences, shows important differences between mouse and human gut epithelium, and reveals insight into how the epithelium responds to the environment and drugs. This comprehensive cell atlas of the healthy adult human intestinal epithelium resolves likely functional differences across anatomic regions along the gastrointestinal tract and advances our understanding of human intestinal physiology.

Sensory neurons control the functions of dendritic cells to guide allergic immunity

Dendritic cells of the innate immune system and sensory neurons of the peripheral nervous system are embedded in barrier tissues and gather information about an organisms' environment. While the mechanisms by which dendritic cells recognize and initiate adaptive immune responses to pathogens is well defined, how they sense allergens is poorly understood. Indeed, allergens induce dendritic cell maturation and migration in vivo, but not in vitro. How are adaptive immune responses to allergens initiated if dendritic cells do not directly sense allergens? Sensory neurons release neuropeptides within minutes of allergen exposure. Recent evidence demonstrated that while neuropeptides modify dendritic cell function during pathogen responses, they are required for dendritic cell function during allergic responses. These emerging studies suggest that sensory neurons do not just pass information along to the central nervous system, but also to dendritic cells, particularly during the initiation of adaptive immunity to allergens.

Melanoma therapeutics: a literature review

Melanoma is a relentless type of skin cancer which involves myriad signaling pathways which regulate many cellular processes. This makes melanoma difficult to treat, especially when identified late. At present, therapeutics include chemotherapy, surgical resection, biochemotherapy, immunotherapy, photodynamic and targeted approaches. These interventions are usually administered as either a single-drug or in combination, based on tumor location, stage, and patients' overall health condition. However, treatment efficacy generally decreases as patients develop treatment resistance. Genetic profiling of melanocytes and the discovery of novel molecular factors involved in the pathogenesis of melanoma have helped to identify new therapeutic targets. In this literature review, we examine several newly approved therapies, and briefly describe several therapies being assessed for melanoma. The goal is to provide a comprehensive overview of recent developments and to consider future directions in the field of melanoma.

NF-κB signaling in inflammation and cancer

Since nuclear factor of κ-light chain of enhancer-activated B cells (NF-κB) was discovered in 1986, extraordinary efforts have been made to understand the function and regulating mechanism of NF-κB for 35 years, which lead to significant progress. Meanwhile, the molecular mechanisms regulating NF-κB activation have also been illuminated, the cascades of signaling events leading to NF-κB activity and key components of the NF-κB pathway are also identified. It has been suggested NF-κB plays an important role in human diseases, especially inflammation-related diseases. These studies make the NF-κB an attractive target for disease treatment. This review aims to summarize the knowledge of the family members of NF-κB, as well as the basic mechanisms of NF-κB signaling pathway activation. We will also review the effects of dysregulated NF-κB on inflammation, tumorigenesis, and tumor microenvironment. The progression of the translational study and drug development targeting NF-κB for inflammatory diseases and cancer treatment and the potential obstacles will be discussed. Further investigations on the precise functions of NF-κB in the physiological and pathological settings and underlying mechanisms are in the urgent need to develop drugs targeting NF-κB for inflammatory diseases and cancer treatment, with minimal side effects.

The Immunopathobiology of SARS-CoV-2 Infection

Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can lead to coronavirus disease 2019 (COVID-19). Virus-specific immunity controls infection, transmission and disease severity. With respect to disease severity, a spectrum of clinical outcomes occur associated with age, genetics, comorbidities and immune responses in an infected person. Dysfunctions in innate and adaptive immunity commonly follow viral infection. These are heralded by altered innate mononuclear phagocyte differentiation, activation, intracellular killing and adaptive memory, effector, and regulatory T cell responses. All of such affect viral clearance and the progression of end-organ disease. Failures to produce effective controlled antiviral immunity leads to life-threatening end-organ disease that is typified by the acute respiratory distress syndrome. The most effective means to contain SARS-CoV-2 infection is by vaccination. While an arsenal of immunomodulators were developed for control of viral infection and subsequent COVID-19 disease, further research is required to enable therapeutic implementation.

Anti-viral and pro-inflammatory functions of Toll-like receptors during gamma-herpesvirus infections

Toll-like receptors (TLRs) control anti-viral responses both directly in infected cells and in responding cells of the immune systems. Therefore, they are crucial for responses against the oncogenic γ-herpesviruses Epstein-Barr virus and Kaposi's sarcoma-associated herpesvirus and the related murine virus MHV68, which directly infect immune system cells. However, since these viruses also cause lifelong persistent infections, TLRs may also be involved in modulation of inflammation during latent infection and contribute to virus-driven tumorigenesis. This review summarizes work on both of these aspects of TLR/γ-herpesvirus interactions, as well as results showing that TLR activity can drive these viruses' re-entry into the replicative lytic cycle.