Innate Immune Receptors Research Articles

RNA viruses, TLRs, and cytokines: the perfect storm?

The interactions between virus and the host immune response are nuanced and intricate. The cytokine response arguably plays a central role in dictating the outcome of virus infection, balancing inflammation and healing, which is crucial to resolving infection without destructive immunopathologies. Early innate immune responses are key to the generation of a beneficial or detrimental immune response. These initial responses are regulated by a plethora of surface bound, endosomal, and cytoplasmic innate immune receptors known as pattern recognition receptors. Of these, the Toll like receptors (TLRs) play an important role in the induction of cytokines during virus infection. Recognizing pathogen-associated molecular patterns (PAMPs) such as viral proteins and/or nucleotide sequences, the TLRs act as sentinels for the initiation and propagation of immune responses. TLRs are important receptors for initiating the innate response to single-stranded RNA (ssRNA) viruses like influenza A virus (IAV), severe acute respiratory syndrome coronavirus-1 (SARS-CoV-1), SARS-CoV-2, Middle East respiratory syndrome coronavirus (MERS-CoV), dengue virus and Ebola virus. Infection with these viruses is also associated with aberrant expression of proinflammatory cytokines that contribute to a harmful cytokine storm response. Herein we discuss the connections between these ssRNA viruses, cytokine storm, and the roles for TLRs.

High expression of nucleotide-binding oligomerization domain protein 1 correlates with poor prognosis and immune cell infiltration in Glioblastoma Multiforme patients

Nucleotide-binding oligomerization domain protein 1 (NOD1) is one of the innate immune receptors that has been associated with tumorigenesis and abnormally expressed in various cancers. However, the role of NOD1 in Glioblastoma Multiforme (GBM) has not been investigated. We used the Tumor Immune Estimate Resource (TIMER) database to compare the differential expression of NOD1 in various tumors. NOD1 expression in GBM was further validated in the GEO database, and the survival of NOD1 was assessed by the Kaplan–Meier method. Clinical samples were collected to validate NOD1 expression. GSEA was carried out to expound on NOD1-related pathways involved in GBM. NOD1 co-expression and enrichment analysis were performed using the Linked Omics database and R software. The relationship between immune infiltrates and NOD1 expression was assessed by TIMER. Besides, the correlation between NOD1 and immune signatures (immunomodulators and chemokine) was evaluated by TISIDB. We found that NOD1 expression was significantly upregulated in GBM patients, and higher expression of NOD1 was associated with a poor prognosis. GSEA and enrichment analysis revealed that NOD1 might play a vital role in immune response and GBM progression. TIMER analysis showed a positive correlation between NOD1 expression and 17 types of tumor-infiltrating immune cells. Moreover, NOD1 expression was positively correlated with the expression of chemokine and immunomodulators in GBM. Overall, our findings suggest that NOD1 is a promising prognostic biomarker and is associated with immune cell infiltration in GBM, making it a potential diagnostic biomarker for this aggressive brain cancer.

Clec12a controls colitis by tempering inflammation and restricting expansion of specific commensals.

Microbiota composition regulates colitis severity, yet the innate immune mechanisms that control commensal communities and prevent disease remain unclear. We show that the innate immune receptor, Clec12a, impacts colitis severity by regulating microbiota composition. Transplantation of microbiota from a Clec12a-/- animal is sufficient to worsen colitis in wild-type mice. Clec12a-/- mice have expanded Faecalibaculum rodentium, and treatment with F.rodentium similarly exacerbates disease. However, Clec12a-/- animals are resistant to colitis development when rederived into an 11-member community, underscoring the role of specific species. Colitis in Clec12a-/- mice is dependent on monocytes, and cytokine and sequencing analysis in Clec12a-/- macrophages and serum shows enhanced inflammation with a reduction in phagocytic genes. F.rodentium specifically binds to Clec12a, and Clec12a-/--deficient macrophages are impaired in their ability to phagocytose F.rodentium. Thus, Clec12a contributes to an innate-immune-surveillance mechanism that controls the expansion of potentially harmful commensals while limiting inflammation.

Astrocytes contribute to toll-like receptor 2-mediated neurodegeneration and alpha-synuclein pathology in a human midbrain Parkinson’s model

BackgroundParkinson’s disease (PD) is characterised by degeneration of ventral midbrain dopaminergic (DA) neurons and abnormal deposition of α-synuclein (α-syn) in neurons. Activation of the innate immune pathogen recognition receptor toll-like receptor 2 (TLR2) is associated with exacerbation of α-syn pathology. TLR2 is increased on neurons in the PD brain, and its activation results in the accumulation and propagation of α-syn through autophagy inhibition in neurons. In addition to the aggregation and propagation of pathological α-syn, dysfunction of astrocytes may contribute to DA neuronal death and subsequent clinical progression of PD. However, the role of astrocytes in TLR2-mediated PD pathology is less explored but important to address, given that TLR2 is a potential therapeutic target for PD.MethodsInduced pluripotent stem cells from three controls and three PD patients were differentiated into a midbrain model comprised of neurons (including DA neurons) and astrocytes. Cells were treated with or without the TLR2 agonist Pam3CSK4, and α-syn pathology was seeded using pre-formed fibrils. Confocal imaging was used to assess lysosomal function and α-syn pathology in the different cell types, as well as DA neuron health and astrocyte activation.ResultsTLR2 activation acutely impaired the autophagy lysosomal pathway, and potentiated α-syn pathology seeded by pre-formed fibrils in PD neurons and astrocytes, leading to degeneration and loss of DA neurons. The astrocytes displayed impaired chaperone-mediated autophagy reducing their ability to clear accumulated α-syn, and increases of A1 neurotoxic phenotypic proteins SerpinG1, complement C3, PSMB8 and GBP2. Moreover, the phenotypic changes in astrocytes correlated with a specific loss of DA neurons.ConclusionsTaken together, these results support a role for astrocyte dysfunction in α-syn accumulation and DA neuronal loss following TLR2 activation in PD.

Role of innate immune receptors in the psoriasis development

Psoriasis is an immune-mediated autoimmune inflammatory skin disease with a prevalence of 2 to 3% worldwide. In the psoriasis development and pathogenesis an important role is played by disorders in the immune system. Disruption of the innate and adaptive immune response mechanisms with the involvement of keratinocytes leads to the initiation and maintenance of inflammation. Immune reactions are activated in the skin, in which various cells participate (macrophages, dendritic cells, mast cells, innate immune lymphoid cells, melanocytes, keratinocytes, Langerhans cells and γδT cells; T and B cells; epithelial endothelial and stromal cells of the skin), each of which expresses pattern recognition receptors that respond to pathogens and cell damage itself. Many of these receptors, in particular toll-like receptors and NOD-like receptors play an important role in the pathogenesis of psoriasis. The associated innate receptors signaling cascades that activate in the skin cells may become potential targets for the treatment of this disease. To date, there are several approved drugs for biological therapy of psoriasis. The study of the role of the innate immune cells receptors in inflammatory skin pathologies requires further exploration and new developments.

Cooperative tumor inhibition by CpG-oligodeoxynucleotide and cyclic dinucleotide in head and neck cancer involves T helper cytokine and macrophage phenotype reprogramming

Head and neck cancer ranks as the sixth most common cancer worldwide, highlighting the critical need for the development of new therapies to enhance treatment efficacy. The activation of innate immune receptors given their potent immune stimulatory properties aid in the eradication of cancer cells. In this study, we investigated the immune mechanism and anti-tumor function of a Toll-like receptor 9 (TLR9) agonist, CpG-oligodeoxynucleotide-2722 (CpG-2722), in combination with cyclic dinucleotides, which are agonists of stimulator of interferon genes (STING). Our results revealed that CpG-2722 stimulation increased the expression of Th1 pro-inflammatory cytokines. Stimulation by STING agonists exhibited lower expression of Th1 cytokines but higher expression of Th2 cytokines compared to CpG-2722. However, the combination of these two agonists significantly enhanced Th1 cytokines while reducing Th2 cytokines. Moreover, in vivo experiment showed that both CpG-2722 and 2'3'-c-di-AMP suppressed head and neck tumor growth, with their combination proving more effective than the use of these agonists alone. The combined treatment cooperatively promoted the production of Th1 cytokines and type I interferons, while suppressing Th2 cytokines in the tumors as observed in vitro. Additionally, it led to the accumulation of M1 macrophages, dendritic cells, and T cells, shaping a favorable tumor microenvironment for T cell-mediated tumor killing. The anti-tumor activity of the CpG-2722 and 2'3'-c-di-AMP combination depends on the macrophage presence but does not directly activate M1 macrophage polarization, instead working through a reprogrammed cytokine profile. Furthermore, this combination shows a cooperative anti-tumor activity with anti-PD-1 in treating head and neck tumors. Overall, these findings highlight a Th response and macrophage phenotype reprograming involved functional mechanism underlying the cooperative activity of the combination of TLR9 and STING agonists in the immunotherapy of head and neck cancer.

Leptospira spp. is recognized by TLR2 and induces IFN-β and IFN-λ expression in smegma from naturally infected bulls.

Leptospirosis, a zoonosis with a wide worldwide distribution, causes significant reproductive losses in cattle. The genital presentation of the disease has been reported, and its understanding is crucial for the implementation of adequate sanitary measures. Although Leptospira spp. modulate innate immunity, the response in the genital mucosa of bulls is unknown. The objective of this work was to evaluate the expression of innate immune receptors and cytokines in smegma from bulls with genital infection by Leptospira spp. To do so, routine preputial scraping samples were selected from breeding bulls from four establishments in the Azul District, Buenos Aires, Argentina with no reproductive problems, which were previously evaluated for the presence of Leptospira spp. DNA by qPCR detection of the secY gene. The relative gene expression of TLR2, TLR4, IFN-β and IFN-λ in the smegma samples of animals infected with Leptospira spp. was determined by RT-qPCR, with subsequent analysis of the results using REST software. The expression of TLR2 was significantly increased in animals infected with Leptospira spp. compared to uninfected control animals (4-fold), while TLR4 did not show differences. Likewise, both IFN-β and IFN-λ were significantly increased in smegma of infected animals (3.5 and 3.1-fold, respectively). Therefore, this work shows that genital infection of Leptospira spp. in bulls generates and modulates a local innate immune response, with an association between the presence of Leptospira spp. DNA and the expression levels of TLR2, IFN-β and IFN-λ.

Buprenorphine Induces Human Fetal Membrane Sterile Inflammation.

Opioid-use disorder (OUD) during pregnancy has increased in the United States to critical levels and is a leading cause of maternal morbidity and mortality. Untreated OUD is associated with pregnancy complications in particular, preterm birth. Medications for OUD, such as buprenorphine, are recommended with the added benefit that treatment during pregnancy increases treatment post-partum. However, the rate of preterm birth in individuals using illicit opioids or being treated with opioid agonist therapeutics is double that of the general population. Since inflammation in the placenta and the associated fetal membranes (FM) is a common underlying cause of preterm birth, we sought to determine if the opioid, buprenorphine, induces sterile inflammation in human FMs and to examine the mechanisms involved. Using an established in vitro human FM explant system, we report that buprenorphine significantly increased FM secretion of the inflammatory cytokine IL-6; the neutrophilic chemokine IL-8; and the inflammasome-mediated cytokine IL-1β, mirroring the inflammatory profile commonly seen at the maternal-fetal interface in preterm birth. Other factors that were elevated in FMs exposed to buprenorphine included the mediators of membrane weakening, prostaglandin E2 (PGE2), and matrix metalloproteinases, MMP1 and MMP9. Furthermore, this sterile inflammatory and weakening FM response induced by buprenorphine was mediated in part by innate immune Toll-like receptor 4 (TLR4), the NLRP3 inflammasome, the μ-opioid receptor, and downstream NFκB and ERK/JNK/MAPK signaling. This may provide the mechanistic link between opioid use in pregnancy and the elevated risk for preterm birth. Since there are adverse consequences of not treating OUD, our findings may help identify ways to mitigate the impact opioids have on pregnancy outcomes while allowing the continuation of maintenance therapy.

Forced MyD88 signaling in microglia impacts the production and survival of regenerated retinal neurons.

Inflammation and microglia appear to be key factors influencing the outcome of retinal regeneration following acute retinal damage. Despite such findings, direct connection of microglia-specific inflammatory factors as drivers of regenerative responses in the retina are still not defined, and intracellular pathways activated to stimulate such signals from microglia are currently unknown. We became interested in MyD88 regulation in microglia because transcriptomic datasets suggest myd88 could be regulated temporally in zebrafish microglia responding to damage in the central nervous system. MyD88 is an intracellular molecular adaptor that initiates signaling cascades downstream of several innate immune receptors, and probably most well-known for inducing gene expression of pro-inflammatory factors. Using zebrafish, which spontaneously regenerate retinal neurons after acute retinal damage, we studied the effects of overactivation of MyD88 signaling in microglia and macrophages on the Müller glia-mediated regenerative response. Our results indicate that increased MyD88 signaling in microglia/macrophages impacts the initial response of Müller glia entering a regenerative response after acute, neurotoxin-induced retinal damage to inner retinal neurons. In addition, increased MyD88 signaling in microglia/macrophages resulted in reduced survival of inner retinal neurons in regenerated retinas. This work supports the idea that temporal control of inflammatory signaling is a key component in the production of MG-derived progenitors yet further indicates that such control is important for differentiation and survival of regenerated neurons.

Bioinformatics designing of an mRNA vaccine for Mokola virus (MOKV) using immunoinformatics as a secure strategy for successful vaccine development

The Mokola Virus belongs to the family Rhabdoviridae and is genotype 3 of the Lyssavirus genera. A small number of cases of animal and human encephalomyelitis, mainly scattered over sub-Saharan Africa, have been linked to the Mokola Virus (MOKV). Currently there is no vaccine to protect against MOKV infection in people or animals. It has been proven that rabies vaccination does not confer immunity against MOKV infection, even though MOKV and the rabies virus are related. Using immunoinformatics approaches, this study designed an mRNA vaccine that can protect against all the five glycoproteins of the Mokola virus. NCBI was used to obtain the viral sequences, which were then screened for antigenicity, allergenicity, toxicity, B-cell epitopes, CD8 + T lymphocytes (CTL), and CD4 + T lymphocytes (HTL). These epitopes were used in the construction of the vaccine. Some extra co-translational residues were added to the mRNA vaccine construct. Its molecular weight is 129.19083 kDa, and its estimated pI is 8.58. It interacts rather steadily and with limited deformability with TLR 3, among other human innate immune receptors. Overall, the results show that the produced candidate vaccine is non-allergen, non-toxic, and can elicit T–cell and B–cell immune responses. These findings can further be subjected to in-vivo and in-vitro techniques for validation.

CD47 and thrombospondin-1 contribute to immune evasion by Porphyromonas gingivalis

Porphyromonas gingivalis is a gram-negative anaerobic bacterium linked to periodontal disease. Remarkably, P. gingivalis thrives in an inflamed environment rich in activated neutrophils. Toll-like receptor 2 (TLR2) recognition is required for P. gingivalis to evade innate immune killing; however, the mechanisms through which P. gingivalis uncouples host inflammation from bactericidal activity are only partially known. Since integrin activation and alternative signaling are implicated in P. gingivalis TLR2-mediated immune escape, we explored the role of CD47, a widely expressed integrin-associated protein known to suppress phagocytosis and implicated as an interacting partner with other innate immune receptors. We found that CD47 associates with TLR2, and blocking CD47 leads to decreased intracellular P. gingivalis survival in macrophages in a manner dependent on the bacterial major fimbria. In vivo, CD47 knock-out mice cleared P. gingivalis more efficiently than wild-type mice. Next, we found increased expression and secretion of the CD47 ligand thrombospondin-1 (TSP-1) following P. gingivalis infection. Secreted TSP-1 broadly protected P. gingivalis and other periodontitis-associated bacterial species from neutrophil bactericidal activity. Therefore, CD47-TLR2 cosignaling in response to P. gingivalis induces TSP-1 that in turn suppresses neutrophil activity, an effect that can explain how species such as P. gingivalis survive in an inflamed environment and cause dysbiosis.

A microenvironment-modulating dressing with proliferative degradants for the healing of diabetic wounds.

Diabetic wounds are usually entangled in a disorganized and self-perpetuating microenvironment and accompanied by a prolonged delay in tissue repair. Sustained and coordinated microenvironment regulation and tissue regeneration are key to the healing process of diabetic wounds, yet they continue to pose a formidable challenge. Here we report a rational double-layered dressing design based on chitosan and a degradable conjugated polymer polydiacetylene, poly(deca-4,6-diynedioic acid) (PDDA), that can meet this intricate requirement. With an alternating ene-yne backbone, PDDA degrades when reacting with various types of reactive oxygen species (ROS), and more importantly, generates proliferative succinic acid as a major degradant. Inheriting from PDDA, the developed PDDA-chitosan double layer dressing (PCD) can eliminate ROS in the microenvironment of diabetic wounds, alleviate inflammation, and downregulate gene expression of innate immune receptors. PCD degradation also triggers simultaneous release of succinic acid in a sustainable manner, enabling long-term promotion on tissue regeneration. We have validated the biocompatibility and excellent performance of PCD in expediting the wound healing on both diabetic mouse and porcine models, which underscores the significant translational potential of this microenvironment-modulating, growth-promoting wound dressing in diabetic wounds care.

RIPK2 Is Crucial for the Microglial Inflammatory Response to Bacterial Muramyl Dipeptide but Not to Lipopolysaccharide.

Receptor-interacting serine/threonine protein kinase 2 (RIPK2) is a kinase that is essential in modulating innate and adaptive immune responses. As a downstream signaling molecule for nucleotide-binding oligomerization domain 1 (NOD1), NOD2, and Toll-like receptors (TLRs), it is implicated in the signaling triggered by recognition of microbe-associated molecular patterns by NOD1/2 and TLRs. Upon activation of these innate immune receptors, RIPK2 mediates the release of pro-inflammatory factors by activating mitogen-activated protein kinases (MAPKs) and nuclear factor-kappa B (NF-κB). However, whether RIPK2 is essential for downstream inflammatory signaling following the activation of NOD1/2, TLRs, or both remains controversial. In this study, we examined the role of RIPK2 in NOD2- and TLR4-dependent signaling cascades following stimulation of microglial cells with bacterial muramyl dipeptide (MDP), a NOD2 agonist, or lipopolysaccharide (LPS), a TLR4 agonist. We utilized a highly specific proteolysis targeting chimera (PROTAC) molecule, GSK3728857A, and found dramatic degradation of RIPK2 in a concentration- and time-dependent manner. Importantly, the PROTAC completely abolished MDP-induced increases in iNOS and COX-2 protein levels and pro-inflammatory gene transcription of Nos2, Ptgs2, Il-1β, Tnfα, Il6, Ccl2, and Mmp9. However, increases in iNOS and COX-2 proteins and pro-inflammatory gene transcription induced by the TLR4 agonist, LPS, were only slightly attenuated with the GSK3728857A pretreatment. Further findings revealed that the RIPK2 PROTAC completely blocked the phosphorylation and activation of p65 NF-κB and p38 MAPK induced by MDP, but it had no effects on the phosphorylation of these two mediators triggered by LPS. Collectively, our findings strongly suggest that RIPK2 plays an essential role in the inflammatory responses of microglia to bacterial MDP but not to LPS.

The microglial innate immune receptor TREM2 participates in fear memory formation through excessive prelimbic cortical synaptic pruning.

Fear memory formation has been implicated in fear- and stress-related psychiatric disorders, including post-traumatic stress disorder (PTSD) and phobias. Synapse deficiency and microglial activation are common among patients with PTSD, and induced in animal models of fear conditioning. Increasing studies now focus on explaining the specific mechanisms between microglia and synapse deficiency. Though newly-identified microglia regulator triggering receptor expressed on myeloid cells 2 (TREM2) plays a role in microglial phagocytic activity, its role in fear-formation remains unknown. We successfully constructed a fear- formation model by foot-shock. Four days after foot-shock, microglial capacity of synaptic pruning was investigated via western blotting, immunofluorescence and Golgi-Cox staining. Prelimbic chemical deletion or microglia inhibition was performed to detect the role of microglia in synaptic loss and neuron activity. Finally, Trem2 knockout mice or wild-type mice with Trem2 siRNA injection were exposed to foot-shock to identify the involvement of TREM2 in fear memory formation. The results herein indicate that the foot-shock protocol in male mice resulted in a fear formation model. Mechanistically, fear conditioning enhanced the microglial capacity for engulfing synapse materials, and led to glutamatergic neuron activation in the prelimbic cortex. Prelimbic chemical deletion or microglia inhibition improved fear memory formation. Further investigation demonstrated that TREM2 regulates microglial phagocytosis, enhancing synaptic pruning. Trem2 knockout mice showed remarkable reductions in prelimbic synaptic pruning and reduced neuron activation, with decreased fear memory formation. Our cumulative results suggest that prelimbic TREM2-mediated excessive microglial synaptic pruning is involved in the fear memory formation process, leading to development of abnormal stress-related behavior.

Preclinical development of SGN-CD47M: Protease-activated antibody technology enables selective tumor targeting of the innate immune checkpoint receptor CD47.

CD47 is a cell surface glycoprotein that is expressed on normal human tissues and has a key role as a marker of self. Tumor cells have coopted CD47 overexpression to evade immune surveillance and thus blockade of CD47 is a highly active area of clinical exploration in oncology. However, clinical development of CD47-targeted agents has been complicated by its robust expression in normal tissues and the toxicities that arise from blocking this inhibitory signal. Further, pro-phagocytic signals are not uniformly expressed in tumors and antibody blockade alone is often not sufficient to drive antitumor activity. The inclusion of an IgG1 antibody backbone into therapeutic design has been shown to serve as an additional pro-phagocytic signal but also exacerbates toxicities in normal tissues. Therefore, a need persists for more selective therapeutic modalities targeting CD47. To address these challenges, we developed SGN-CD47M, a humanized anti-CD47 IgG1 monoclonal antibody linked to novel masking peptides through linkers designed to be cleaved by active proteases enriched in the tumor microenvironment. Masking technology has the potential to increase the amount of drug that reaches the tumor microenvironment, while concomitantly reducing systemic toxicities. We demonstrate that SGN-CD47M is well tolerated in cynomolgus monkeys and displays a 20-fold improvement in tolerability to hematologic toxicities when compared to the unmasked antibody. SGN-CD47M also displays preferential activation in the tumor microenvironment that leads to robust single-agent antitumor activity. For these reasons, SGN-CD47M may have enhanced antitumor activity and improved tolerability relative to existing therapies that target the CD47-SIRPα interaction.

TLR7 deficiency alleviated myocardial ischemia reperfusion injury via regulating macrophage-neutrophil interaction

Abstract Background Toll-like receptor 7 (TLR7) is an intracellular innate immune receptor activated by single-stranded RNA. We previously reported that TLR7 could recognize RNA from dying cardiac cells and thereby deteriorating post myocardial infarction left ventricular remodeling. However, its effect on myocardial ischemia reperfusion (IR) injury is still unknown. Purpose In this study, we aimed to investigate the role of TLR7 in myocardial IR injury and the underlying mechanisms. Methods C57BL/6J wild type (WT) and TLR7 deficient (TLR7-/-) mice underwent left anterior descending artery occlusion for 30min followed by reperfusion. Myocardial infarct size was measured by Evan’s blue and TTC staining. mRNA expression levels of cytokines and phagocytosis-related receptors were detected by qPCR. TUNEL assay was conducted to determine apoptosis in the heart. Influx of neutrophils and macrophages in ischemic myocardium was analyzed by flow cytometry and Histone Cit3 was imaged to examine formation of neutrophils extracellular traps (NETs), cardiac function was evaluated by echocardiography during post-IR injury follow-up. Results TLR7 expression was up-regulated after IR injury in ischemic myocardium of WT mice. Compared to WT mice, fewer apoptotic cells and smaller infarct size (34±2% vs. 23±3% of area at risk, p<0.01) were observed in TLR7-/- mice at 24 hours post-IR, which was accompanied by reduced inflammatory cytokines (IL-1β: 110.5±14.1 vs. 54.8±13.7, p<0.05; TNF-α: 4.6±1.0 vs. 2.0±0.4, p<0.05) and increased anti-inflammatory factors (TNF-β: 2.9±0.3 vs. 8.6±2.6, p<0.05; IL-10: 14.2±2.1 vs. 32.3±8.8, p<0.05). Surprisingly, although the influx of neutrophils and macrophages increased to a similar extent in WT and TLR7-/- mice, the latter exhibited remarkably less NETs formation and enhanced macrophage phagocytosis in the infarct region. Moreover, TLR7 deficiency improved cardiac function, as indicated by increased left ventricular ejection fraction (LVEF) and fraction shortening (FS) at 56d post-IR. Conclusions TLR7 deficiency alleviates myocardial IR injury and improves cardiac function probably via enhancing macrophage clearance of NETs in the injured myocardium.TLR7 deficiency in cardiac functionTLR7 deficiency decreased NETs formation

Pangenome analysis of five representative Tropheryma whipplei strains following multiepitope-based vaccine design via immunoinformatic approaches.

Whipple disease caused by Tropheryma whipplei a gram-positive bacterium is a systemic disorder that impacts not only the gastrointestinal tract but also the vascular system, joints, central nervous system, and cardiovascular system. Due to the lack of an approved vaccine, this study aimed to utilize immunoinformatic approaches to design multiepitope -based vaccine by utilizing the proteomes of five representative T. whipplei strains. The genomes initially comprised a total of 4,844 proteins ranging from 956 to 1012 proteins per strain. We collected 829 nonredundant lists of core proteins, that were shared among all the strains. Following subtractive proteomics, one extracellular protein, WP_033800108.1, a WhiB family transcriptional regulator, was selected for the chimeric-based multiepitope vaccine. Five immunodominant epitopes were retrieved from the WhiB family transcriptional regulator protein, indicating MHC-I and MHC-II with a global population coverage of 70.61%. The strong binding affinity, high solubility, nontoxicity, nonallergenic properties and high antigenicity scores make the selected epitopes more appropriate. Integration of the epitopes into a chimeric vaccine was carried out by applying appropriate adjuvant molecules and linkers, leading to the vaccine construct having enhanced immunogenicity and successfully eliciting both innate and adaptive immune responses. Moreover, the abilityof the vaccine to bind TLR4, a core innate immune receptor, was confirmed. Molecular dynamics simulations have also revealed the promising potential stability of the designed vaccine at 400 ns. In summary, we have designed a potential vaccine construct that has the ability not only to induce targeted immunogenicity for one strain but also for global T. whipplei strains. This study proposes a potential universal vaccine, reducing Whipple's disease risk and laying the groundwork for future research on multi-strain pathogens.

Alterations in expression of TLR2 and TLR4 during successful and pathological aging

The generally accepted theory of aging is the theory of inflammaging. The leading role in its development is played by the mechanisms of innate immunity. Key receptors of innate immunity are TLRs. The patterns of age-related changes in the functioning of the TLR system remain the subject of study. The purpose of the work is to study the expression of TLR2 and TLR4 receptors in peripheral blood cells of centenarians and elderly people at the level of genes and surface molecules. The study analyzed the expression of genes and molecules TLR2 and TLR4 in young donors (n = 50), elderly people (n = 50) and centenarians (n = 100). Analysis of TLR2 and TLR4 gene expression was carried out using RT-PCR. Determination of surface expression of TLR2 and TLR4 was carried out using flow cytofluorimetry. This study is the first to analyze the age-related dynamics of expression of genes and molecules TLR2 and TLR4. It was revealed that in groups of elderly patients and long-livers, TLR2 expression is increased both at the gene and on the cell surface, compared to young donors. In contrast, TLR4 expression decreased with age. Studied groups of patients were divided depending on the aging phenotype into two subgroups: successful and pathological aging. In elderly individuals, TLR2 is increased in both phenotypes, while TLR4 is decreased in the pathological aging. In the group of centenarians with a pathological aging, a decrease in both TLR2 and TLR4 is observed, compared with young. In long-livers with successful aging, an increase in TLR2 expression was observed at the gene and protein level and TLR4 expression was comparable to the group of young individuals. Identified changes in the expression of TLR2 and TLR4, observed in different age groups, can be considered as markers of various aging phenotypes.

Preclinical and first-in-human evaluation of AL002, a novel TREM2 agonistic antibody for Alzheimer’s disease

BackgroundVariants of the gene triggering receptor expressed on myeloid cells-2 (TREM2) increase the risk of Alzheimer’s disease (AD) and other neurodegenerative disorders. Signaling by TREM2, an innate immune receptor expressed by microglia, is thought to enhance phagocytosis of amyloid beta (Aβ) and other damaged proteins, promote microglial proliferation, migration, and survival, and regulate inflammatory signaling. Thus, TREM2 activation has potential to alter the progression of AD. AL002 is an investigational, engineered, humanized monoclonal immunoglobulin G1 (IgG1) antibody designed to target TREM2. In AD mouse models, an AL002 murine variant has been previously shown to induce microglial proliferation and reduce filamentous Aβ plaques and neurite dystrophy.MethodsPreclinical studies assessed the safety, tolerability, pharmacokinetics, and pharmacodynamics of AL002 in cynomolgus monkeys. INVOKE-1 (NCT03635047) was a first-in-human phase 1, randomized, placebo-controlled, double-blind study assessing the safety, tolerability, PK, and PD of AL002 administered as single ascending doses (SAD) in healthy volunteers.ResultsIn cynomolgus monkeys, weekly intravenous injections of AL002 for 4 weeks were well tolerated, dose-dependently decreased soluble TREM2 (sTREM2) in cerebrospinal fluid (CSF) and total TREM2 in hippocampus and frontal cortex, and increased biomarkers of TREM2 signaling in CSF and brain. In the phase 1 study of 64 healthy volunteers, a single intravenous infusion of AL002 demonstrated brain target engagement based on a dose-dependent reduction of sTREM2 in CSF and parallel increases in biomarkers of TREM2 signaling and microglia recruitment. Single-dose AL002 showed central nervous system penetrance and was well tolerated, with no treatment-related serious adverse events over 12 weeks.ConclusionsThese findings support the continued clinical development of AL002 for AD and other neurodegenerative diseases in which TREM2 activation may be beneficial. AL002 is currently being tested in a phase 2, randomized, double-blind, placebo-controlled study in early AD.Trial registrationClinicaltrials.gov, NCT03635047. Registered on August 15, 2018, https://www.clinicaltrials.gov/study/NCT03635047.

Mechanisms of action of fungal polysaccharides and their therapeutic effect.

The purpose of this article is to discuss the relationship between the therapeutic bioactivity of basidial fungal polysaccharides (BFPs) BFPs and their structural characteristics and conformational features, as well as to characterize the mechanisms of action of BFPs in diseases of various origins. The review was conducted using the PubMed (Medline), Scopus, Web of Science and the Russian Science Citation Index databases. 8645 records were identified, of which 5250 were studies (86 were randomized controlled trials). The period covered is from 1960 to the present. The most significant studies conducted mainly in Southeast Asian countries were selected for the review. Based on clinical studies, as well as the results obtained on in vivo, in vitro and ex vivo models, it has been proven that BFPs have diverse and highly effective biological activity in the human body in various diseases. The production of BFPs-based vaccines is an innovative strategy from a clinical and biochemical point of view, since as potential immunoprotective and low-toxic biopolymers they have innate immune receptors in the body. Promising results have been obtained in the development of antidiabetic drugs, probiotic, renoprotective and neurodegenerative dietary supplements. The biological activity, mechanism of action and specific therapeutic effect of BFPs largely depend on their structural and physicochemical characteristics. BFPs as multifunctional macromolecular complexes with low toxicity and high safety are ideal as new powerful pharmaceuticals for the treatment and prevention of many diseases.