Toll-Like Receptors as a Therapeutic Target in the Era of Immunotherapies

TLR4 deficiency does not alter glaucomatous progression in a mouse model of chronic glaucoma

Glaucoma is a leading cause of irreversible blindness worldwide. Toll-like receptor 4 (TLR4) is a pattern-recognition transmembrane receptor that induces neuroinflammatory processes in response to injury. Tlr4 is highly expressed in ocular tissues and is known to modulate inflammatory processes in both anterior and posterior segment tissues. TLR4 activation can lead to mitochondrial dysfunction and metabolic deficits in inflammatory disorders. Due to its effects on inflammation and metabolism, TLR4 is a candidate to participate in glaucoma pathogenesis. It has been suggested as a therapeutic target based on studies using acute models, such as experimentally raising IOP to ischemia-inducing levels. Nevertheless, its role in chronic glaucoma needs further evaluation. In the current study, we investigated the role of TLR4 in an inherited mouse model of chronic glaucoma, DBA/2J. To do this, we analyzed the effect of Tlr4 knockout (Tlr4-/-) on glaucoma in DBA/2J mice. Our studies found no significant differences in intraocular pressure, iris disease, or glaucomatous progression in Tlr4-/- compared to Tlr4+/+ DBA/2J mice. Our data do not support a role for TLR4 as a treatment target in chronic glaucoma.

DNA-RNA hybrids in inflammation: sources, immune response, and therapeutic implications

Cytoplasmic DNA-RNA hybrids are emerging as important immunogenic nucleic acids, that were previously underappreciated. DNA-RNA hybrids, formed during cellular processes like transcription and replication, or by exogenous pathogens, are recognized by pattern recognition receptors (PRRs), including cGAS, DDX41, and TLR9, which trigger immune responses. Post-translational modifications (PTMs) including ubiquitination, phosphorylation, acetylation, and palmitoylation regulate the activity of PRRs and downstream signaling molecules, fine-tuning the immune response. Targeting enzymes involved in DNA-RNA hybrid metabolism and PTMs regulation offers therapeutic potential for inflammatory diseases. Herein, we discuss the sources, immune response, and therapeutic implications of DNA-RNA hybrids in inflammation, highlighting the significance of DNA-RNA hybrids as potential targets for the treatment of inflammation.

Gram-negative bacteria activate cellular pathways in plaque microenvironment; Systems biology approach

BACKGROUND

Inflammatory events followed by bacterial infections are related to the progression of the atherosclerosis process. The study investigated the signaling and metabolic pathways of endothelial cells (ECs), macrophages (MQs), vascular smooth muscle cells (VSMCs), and dendritic cells (DCs) after exposure to Gram-negative bacterial infections. Moreover, it aimed at cross-talking and enriching the pathways on the cellular and plaque networks.

METHODS AND MATERIALS

High-throughput expression data series (n = 9) were selected through GEO and MAT data repositories. Upregulated differential expression genes (DEGs) were determined using R software and applied to identify the cellular signaling pathways using Enricher/Reactome tools. Then, the cell networks were visualized using the Cytoscape software and enriched by the pathways of secretory proteins identified using Gene ontology (GO).

RESULTS

The important pathways of the Cytokines (Degree 4, p < 6 × 10-26), and INF (Degree 4, p < 8.6 × 10-31) in ECs, Cytokines (Degree 4, p < 9.35 × 10-8), and GPCR (Degree 3, p < 1.45 × 10-4) in MQs, NOTCH (Degree 6, p < 0.027) in VSMCs, and Cytokines (Degree 4, p < 1.45 × 10-17) in DCs were found to be activated and enriched after exposure to Gram-negative bacterial infections on the cell networks. Furthermore, the Netrin- 1 (Degree 6, p < 0.028), and EGFR (Degree 5, p < 0.036) pathways were activated in the intimal thick/xanthoma plaque network while the innate (Degree 9, p < 8.9 × 10-20) and adaptive (Degree 7, p < 4.1 × 10-12) immune systems pathways were activated in the fibrous cap atheroma plaque network.

CONCLUSION

The study revealed the signaling pathways after exposure to Gram-negative bacterial infections on the cell networks in the vessel microenvironment. Furthermore, the cell cross-talks exacerbated these pathways in cells and unstable plaques.

CLINICAL TRIAL NUMBER

Not applicable.

Nitrate induced hepatic fibrosis in tadpoles of Bufo gargarizans by mediating alterations in toll-like receptor signaling pathways

The nitrate pollution has become an increasingly serious environmental problem worldwide, and the toxic effects of elevated nitrate levels in the environment on aquatic animals remain to be elucidated. The purpose of the present study was to investigate the mechanisms of liver injury to tadpoles after exposure to nitrate from embryonic to metamorphic climax and to assess the recovery process of liver function after cessation of exposure. In the group with continuous nitrate exposure, the livers and thyroid of tadpoles showed remarkably histological lesions, of this with structural disorganization of the hepatocytes, cellular atrophy, and fibrosis, as well as significant reduction in the follicular and colloidal area of the thyroid. Meanwhile, the expression levels of genes related to inflammatory signaling pathways, such as TLR2, TLR6 and NF-κB, were significant elevated. After termination of exposure at Gs23, liver damage (histologic, ultrastructural, and molecular levels) was almost completely recovered, whereas thyroid gland damage was irreversible. Overall, this study shed light on the harmful effects of nitrate pollution on amphibian health and emphasizes the importance of controlling nitrate emissions in the environment.

Role of toll-like receptors in post-COVID-19 associated neurodegenerative disorders?

In the intricate realm of interactions between hosts and pathogens, Toll-like receptors (TLRs), which play a crucial role in the innate immune response, possess the ability to identify specific molecular signatures. This includes components originating from pathogens such as SARS-CoV-2, as well as the resulting damage-associated molecular patterns (DAMPs), the endogenous molecules released after cellular damage. A developing perspective suggests that TLRs play a central role in neuroinflammation, a fundamental factor in neurodegenerative conditions like Alzheimer's and Parkinson's disease (PD). This comprehensive review consolidates current research investigating the potential interplay between TLRs, their signaling mechanisms, and the processes of neurodegeneration following SARS-CoV-2 infection with an aim to elucidate the involvement of TLRs in the long-term neurological complications of COVID-19 and explore the potential of targeting TLRs as a means of implementing intervention strategies for the prevention or treatment of COVID-19-associated long-term brain outcomes.

Endosomal Toll-Like Receptors intermediate negative impacts of viral diseases, autoimmune diseases, and inflammatory immune responses on the cardiovascular system

INTRODUCTION

Cardiovascular disease (CVD) is the leading cause of morbidity globally, with chronic inflammation as a key modifiable risk factor. Toll-like receptors (TLRs), pivotal components of the innate immune system, including TLR-3, -7, -8, and -9 within endosomes, trigger intracellular cascades, leading to inflammatory cytokine production by various cell types, contributing to systemic inflammation and atherosclerosis. Recent research highlights the role of endosomal TLRs in recognizing self-derived nucleic acids during sterile inflammation, implicated in autoimmune conditions like myocarditis.

AREAS COVERED

This review explores the impact of endosomal TLRs on viral infections, autoimmunity, and inflammatory responses, shedding light on their intricate involvement in cardiovascular health and disease by examining literature on TLR-mediated mechanisms and their roles in CVD pathophysiology.

EXPERT OPINION

Removal of endosomal TLRs mitigates myocardial damage and immune reactions, applicable in myocardial injury. Targeting TLRs with agonists enhances innate immunity against fatal viruses, lowering viral loads and mortality. Prophylactic TLR agonist administration upregulates TLRs, protecting against fatal viruses and improving survival. TLRs play a complex role in CVDs like atherosclerosis and myocarditis, with therapeutic potential in modulating TLR reactions for cardiovascular health.

The dual role of toll-like receptors in COVID-19: Balancing protective immunity and immunopathogenesis

Toll-like receptors (TLRs) of human are considered as the most critical immunological mediators of inflammatory pathogenesis of COVID-19. These immunoregulatory glycoproteins are located on the surface and/or intracellular compartment act as innate immune sensors. Upon binding with distinct SARS-CoV-2 ligand(s), TLRs signal activation of different transcription factors that induce expression of the proinflammatory mediators that collectively induce 'cytokine storm'. Similarly, TLR activation is also pivotal in conferring protection to infection and invasion as well as upregulating the tissue repair pathways. This dual role of the human TLRs in deciding the fate of SARS-CoV-2 has made these receptor proteins as the critical mediators of immunoprotective and immunopathogenic consequences associated with COVID-19. Herein, pathbreaking discoveries exploring the immunobiological importance of the TLRs in COVID-19 and developing TLR-directed therapeutic intervention have been reviewed by accessing the up-to-date literatures available in the public domain/databases. In accordance with our knowledge in association with the importance of TLRs' role against viruses and identification of viral particles, they have been recognized as suitable candidates with high potential as vaccine adjuvants. In this regard, the agonists of TLR4 and TLR9 have effective potential in vaccine technology while the others need further investigations. This comprehensive review suggests that basal level expression of TLRs can act as friends to keep our body safe from strangers but act as a foe via overexpression. Therefore, selective inhibition of the overexpressed TLRs appears to be a solution to counteract the cytokine storm while TLR-agonists as vaccine adjuvants could lessen the risk of infection in the naïve population.

TREM-1 and TREM-2 as therapeutic targets: clinical challenges and perspectives

TREM-1 and TREM-2 as Therapeutic Targets: Clinical Challenges and Perspectives.

Epigenetic modulation of immune cells: Mechanisms and implications

Epigenetic modulation of the immune response entails modifiable and inheritable modifications that do not modify the DNA sequence. While there have been many studies on epigenetic changes in tumor cells, there is now a growing focus on epigenetically mediated changes in immune cells of both the innate and adaptive systems. These changes have significant implications for both the body's response to tumors and the development of potential therapeutic vaccines. This study primarily discusses the key epigenetic alterations, with a specific emphasis on pseudouridination, as well as non-coding RNAs and their transportation, which can lead to the development of cancer and the acquisition of new phenotypic traits by immune cells. Furthermore, the advancement of therapeutic vaccinations targeting the tumor will be outlined.

Crosstalk and Prospects of TBK1 in Inflammation

BACKGROUND

TANK-binding kinase 1 (TBK1) is a pivotal mediator of innate immunity, activated by receptors such as mitochondrial antiviral signaling protein (MAVS), stimulator of interferon genes (STING), and TIR-domain-containing adaptor inducing interferon-β (TRIF). It modulates immune responses by exerting influence on the type I interferons (IFN-Is) signaling and the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathways, Over the past few years, TBK1 multifaceted role in both immune and inflammatory responses is increasingly recognized.

METHODS AND RESULTS

This review aims to scrutinize how TBK1 operates within the NF-κB pathway and the interferon regulatory transcription factor 3 (IRF3)-dependent IFN-I pathways, highlighting the kinases and other molecules involved in these processes. This analysis reveals the distinctive characteristics of TBK1's involvement in these pathways. Furthermore, it has been observed that the role of TBK1 in exerting anti-inflammatory or pro-inflammatory effects is contingent upon varying pathological conditions, indicating a multifaceted role in immune regulation.

DISCUSSION

TBK1's evolving role in various diseases and the potential of TBK1 inhibitors as therapeutic agents are explored. Targeting TBK1 may provide new strategies for treating inflammatory disorders and autoimmune diseases associated with IFN-Is, warranting further investigation.

Novel therapeutic receptor agonists and antagonists in allergic conjunctivitis

PURPOSE OF REVIEW

Allergic conjunctivitis is characterized by the development of pathophysiological changes to the ocular surface, which occurs when pro-allergic and pro-inflammatory mediators interact with their cognate receptors expressed on immune and nonimmune cells. Traditional treatments with antihistamines and corticosteroids provide relief, but there is a need for more efficacious and tolerable long-term therapy with a better safety profile. This article aims to provide an overview of the mode of action and clinical application of agonist therapies targeting glucocorticoid, melanocortin, and toll-like receptors, as well as antagonist therapies targeting cytokine, chemokine, integrin, and histamine receptors.

RECENT FINDINGS

There has been considerable advancement in immunology and pharmacology, as well as a greater understanding of the cellular and molecular mechanisms of allergic conjunctivitis. Recent research advancing therapy for allergic conjunctivitis has focused on developing synthetic molecules and biologics that can interfere with the process of the allergic immune reaction.

SUMMARY

This review discusses novel therapeutic receptors being explored agonistically or antagonistically to develop alternative treatment options for allergic conjunctivitis. These novel approaches hold promise for improving the management of allergic eye diseases, offering patients hope for more effective and safer treatment options in the future.

Toll-like receptors 1, 2, 4, 5, and 6 in gastric cancer

Toll-like receptors (TLRs) are expressed on both immune cells and tumor cells, triggering both anti-tumor and pro-tumor responses. Therefore, TLRs have potential as prognostic biomarkers and immunotherapeutic targets. The aim of this study was to investigate TLR1, TLR2, TLR4, TLR5, and TLR6 expression and association with clinicopathological variables and survival in gastric cancer. Immunohistochemical study on cancer specimens from 564 resected gastric cancer patients was performed using tissue microarrays. The association between patient survival and TLR expression was calculated with Cox regression adjusted for confounding factors. Patients with high cytoplasmic TLR2 expression had significantly poorer 5-year survival than the low cytoplasmic TLR2 expression group in multivariate analysis (adjusted HR 1.38, 95% CI 1.11-1.71), and this estimate was similar in intestinal type (adjusted HR 1.33, 95% CI 0.98-1.80) and diffuse type (adjusted HR 1.48, 95% CI 1.06-2.05) histology subgroups. Patients with high cytoplasmic TLR6 expression group had significantly better 5-year survival compared with low cytoplasmic TLR6 expression group in multivariate analysis (adjusted HR 0.74, 95% CI 0.60-0.91). In the subgroup analysis of diffuse type of histology, the 5-year survival was better in high cytoplasmic TLR6 expression group in multivariable analysis (HR 0.62, 95% CI 0.46-0.83). In the intestinal type of histology subgroup, no significant differences between the groups were present. TLR1, TLR4, and TLR5 expression were not associated with 5-year survival. In conclusion, cytoplasmic TLR2 and TLR6 expression seem to have independent prognostic impact in gastric cancer, while TLR1, TLR4, and TLR5 do not.

All-Natural Gelatin-Based Nanoemulsion Loaded with TLR 7/8 Agonist for Efficient Modulation of Macrophage Polarization for Immunotherapy

Macrophages are multifunctional immune cells essential for both innate and adaptive immune responses. Tumor-associated macrophages (TAMs) often adopt a tumor-promoting M2-like phenotype, aiding tumor progression and immune evasion. Reprogramming TAMs to a tumoricidal M1-like phenotype is an emerging target for cancer immunotherapy. Resiquimod, a TLR7/8 agonist, can repolarize macrophages from the M2- to M1-like phenotype but is limited by poor solubility. We developed a gelatin nanoemulsion for the loading and delivery of resiquimod, utilizing eugenol oil as the liquid phase and riboflavin-crosslinked gelatin as a scaffold. These nanoemulsions showed high stability, low toxicity, and effective macrophage repolarization, significantly enhancing pro-inflammatory markers and anticancer activity in co-culture models.

Small molecule innate immune modulators in cancer therapy

Immunotherapy has proved to be a breakthrough in cancer treatment. So far, a bulk of the approved/late-stage cancer immunotherapy are antibody-based. Although these antibody-based drugs have demonstrated great promise, a majority of them are limited due to their access to extracellular targets, lack of oral bioavailability, tumor microenvironment penetration, induction of antibody dependent cytotoxicity etc. In recent times, there has been an increased research focus on the development of small molecule immunomodulators since they have the potential to overcome the aforementioned limitations posed by antibodies. Furthermore, while most biologics based therapeutics that are in clinical use are limited to modulating the adaptive immune system, very few clinically approved therapeutic modalities exist that modulate the innate immune system. The innate immune system, which is the body's first line of defense, has the ability to turn cold tumors hot and synergize strongly with existing adaptive immune modulators. In preclinical studies, small molecule innate immune modulators have demonstrated synergistic efficacy as combination modalities with current standard-of-care immune checkpoint antibodies. In this review, we highlight the recent advances made by small molecule innate immunomodulators in cancer immunotherapy.

The Possible Pathophysiological Role of Pancreatic Stone Protein in Sepsis and Its Potential Therapeutic Implication

According to the current understanding of the pathophysiology of sepsis, key host dysregulated responses leading to organ failure are mediated by innate immunity, through interactions between pathogen-associated molecular patterns (PAMPs) and damaged-associated molecular patterns (DAMPs) binding to four types of pattern recognition receptors (PRRs). PRRs activation triggers the protein kinase cascade, initiating the cellular response seen during sepsis. Pancreatic stone protein (PSP), a C-type lectin protein, is a well-defined biomarker of sepsis. Studies have shown that stressed and immune-activated pancreatic β-cells secrete PSP. Animal studies have shown that PSP injection aggravates sepsis, and that the disease severity score and mortality were directly correlated with the doses of PSP injected. In humans, studies have shown that PSP activates polymorphonuclear neutrophils (PMNs) and aggravates multiple organ dysfunction syndrome. Clinical studies have shown that PSP levels are correlated with disease severity, vasopressor support, progression to organ failure, mechanical ventilation, renal replacement therapy, length of stay, and mortality. As PSP is a C-type lectin protein, it may have a role in activating innate immunity through the C-type lectin receptors (CLRs), which is one of the four PRRs. Herein, we review the literature on PSP and its possible role in the pathophysiology of sepsis, and we discuss its potential therapeutic role.

Toll-like Receptors: Key Players in Squamous Cell Carcinoma Progression

Background/Objectives Lung squamous cell carcinoma (SCC) is one of the major subtypes of lung cancer, characterized by diverse molecular pathways and variable clinical outcomes. This study focused on assessing the levels of TLR-2, TLR-3, TLR-4, TLR-7, TLR-8, and TLR-9 on peripheral blood lymphocytes in patients with newly diagnosed SCC compared to a group of healthy controls, in the context of disease development and patient survival, conducted over three years. The study aimed to investigate the differences in TLR expression between SCC patients and healthy people and to understand their role in the development of the disease and patient survival over three years. Methods: The study included the assessment of TLR-2, TLR-3, TLR-4, TLR-7, TLR-8, and TLR-9 levels on peripheral blood lymphocytes in patients with newly diagnosed SCC and in the control group. The expression of TLRs was measured using flow cytometry, and the soluble forms of the tested TLRs were measured using enzyme-linked immunosorbent assays. All the analyses were conducted over a three-year period from the time patients were recruited to the study. The obtained test results were statistically analyzed. Results: Results showed statistically significant differences in TLR expression between the groups, with higher TLR levels correlating with an advanced stage of disease and poorer survival rates. This suggests that the deregulation of TLR levels may be involved in promoting tumor development and influencing its microenvironment. Conclusions: The research, conducted over three years, indicates the need for further research on the role of TLRs in SCC, including their potential use as therapeutic targets and biomarkers. This may help to increase the effectiveness of standard treatments and improve clinical outcomes in patients with SCC.

Effects of quercetin in preclinical models of Parkinson's disease: A systematic review

Parkinson's disease (PD) is a neurodegenerative disease that affects dopaminergic neurons, thus impairing dopaminergic signalling. Quercetin (QUE) has antioxidant and neuroprotective properties that are promising for the treatment of PD. This systematic review aimed to investigate the therapeutic effects of QUE against PD in preclinical models. The systematic search was performed in PubMed, Scopus and Web of Science. At the final screening stage, 26 articles were selected according to pre-established criteria. Selected studies used different methods for PD induction, as well as animal models. Most studies used rats (73.08%) and mice (23.08%), with 6-OHDA as the main strategy for PD induction (38.6%), followed by rotenone (30.8%). QUE was tested immersed in oil, nanosystems or in free formulations, in varied routes of administration and doses, ranging from 10 to 400 mg/kg and from 5 to 200 mg/kg in oral and intraperitoneal administrations, respectively. Overall, evidence from published data suggests a potential use of QUE as a treatment for PD, mainly through the inhibition of oxidative stress, neuroinflammatory response and apoptotic pathways.

TLR4 deficiency does not alter glaucomatous progression in a mouse model of chronic glaucoma

Glaucoma is a leading cause of irreversible blindness worldwide. Toll-like receptor 4 (TLR4) is a pattern-recognition transmembrane receptor that induces neuroinflammatory processes in response to injury. Tlr4 is highly expressed in ocular tissues and is known to modulate inflammatory processes in both anterior and posterior segment tissues. TLR4 activation can lead to mitochondrial dysfunction and metabolic deficits in inflammatory disorders. Due to its effects on inflammation and metabolism, TLR4 is a candidate to participate in glaucoma pathogenesis. It has been suggested as a therapeutic target based on studies using acute models, such as experimentally raising IOP to ischemia-inducing levels. Nevertheless, its role in chronic glaucoma needs further evaluation. In the current study, we investigated the role of TLR4 in an inherited mouse model of chronic glaucoma, DBA/2J. To do this, we analyzed the effect of Tlr4 knockout (Tlr4 -/-) on glaucoma-associated phenotypes in DBA/2J mice. Our studies found no significant differences in intraocular pressure, iris disease, or glaucomatous progression in Tlr4 -/- compared to Tlr4 +/+ DBA/2J mice. These data do not identify a role for TLR4 in this chronic glaucoma, but further research is warranted to understand its role in other glaucoma models and different genetic contexts.

Immunoexpression pattern of TLR3 and TLR7 in minor salivary gland adenoid cystic carcinoma and its role in prognosis

OBJECTIVES

Adenoid cystic carcinoma (ACC) of the salivary glands has poor long-term prognosis and a high metastatic rate. Toll-like receptors (TLRs), first-line immune activators, have been associated with both tumor progression and suppression. We aimed to study TLR3 and TLR7 behavior in ACC.

MATERIALS AND METHODS

We studied TLR3 and TLR7 immunoexpression of 46 minor salivary gland ACCs diagnosed at the Department of Otorhinolaryngology - Head and Neck Surgery, Helsinki University Hospital, Helsinki, Finland over the period 1974-2012. The associations of TLR3 and TLR7 immunoexpression with clinicopathological factors were evaluated by χ2-test and Fisher's exact test.

RESULTS

In the majority of samples, both TLR3 and TLR7 were immunoexpressed in cytoplasm. The immunoexpression was heterogeneous between individual tumors. Stronger TLR7 immunoexpression associated with recurrence rate and poorer disease-specific survival (DSS). TLR3 did not associate significantly with survival although we found an inverse correlation between TLR3 and TLR7 immunopositivity. Hence, when TLR3 immunoexpression was negative or mild, TLR7 immunoexpression was moderate to strong, and vice versa.

CONCLUSIONS

TLR3 and TLR7 are immunoexpressed in minor salivary gland ACC. TLR7 is potentially an independent prognostic marker for recurrence rate and DSS.

Analysis of Selected Toll-like Receptors in the Pathogenesis and Advancement of Non-Small-Cell Lung Cancer

(1) Background: Non-small-cell lung cancer (NSCLC) represents a significant global health challenge, contributing to numerous cancer deaths. Despite advances in diagnostics and therapy, identifying reliable biomarkers for prognosis and therapeutic stratification remains difficult. Toll-like receptors (TLRs), crucial for innate immunity, now show potential as contributors to cancer development and progression. This study aims to investigate the role of TLR expression as potential biomarkers in the development and progression of NSCLC. (2) Materials and Methods: The study was conducted on 89 patients diagnosed with NSCLC and 40 healthy volunteers, for whom the prevalence of TLR2, TLR3, TLR4, TLR7, TLR8, and TLR9 was assessed on selected subpopulations of T and B lymphocytes in the peripheral blood of recruited patients along with the assessment of their serum concentration. (3) Result: Our study showed several significant changes in NSCLC patients at the beginning of the study. This resulted in a 5-year follow-up of changes in selected TLRs in recruited patients. Due to the high mortality rate of NSCLC patients, only 16 patients survived the 5 years. (4) Conclusions: The results suggest that TLRs may constitute real biomarker molecules that may be used for future prognostic purposes in NSCLC. However, further validation through prospective clinical and functional studies is necessary to confirm their clinical utility. These conclusions may lead to better risk stratification and tailored interventions, benefiting NSCLC patients and bringing medicine closer to precision.

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.

Effects of aging and lifelong aerobic exercise on expression of innate immune components in skeletal muscle of women

This study examined the effects of aging and lifelong aerobic exercise on innate immune system components in the skeletal muscle of healthy women in the basal state and after an unaccustomed resistance exercise (RE) challenge. We also made exploratory between-sex comparisons with our previous report on men. Three groups of women were studied: young exercisers (YE, n = 10, 25 ± 1 yr, V̇o2max: 44 ± 2 mL/kg/min), lifelong aerobic exercisers with a 48 ± 2 yr training history (LLE, n = 7, 72 ± 2 yr, V̇o2max: 26 ± 2 mL/kg/min), and old healthy nonexercisers (OH, n = 10, 75 ± 1 yr, V̇o2max: 18 ± 1 mL/kg/min). Ten Toll-like receptors (TLRs)1-10, TLR adaptors (Myd88, TRIF), and NF-κB pathway components (IκBα, IKKβ) were assessed at the mRNA level in vastus lateralis biopsies before and 4 h after RE [3×10 repetitions, 70% 1-repetition maximum (1RM)]. Basal TLR1-10 expression was minimally influenced by age or LLE in women (TLR9 only; OH > YE, +43%, P < 0.05; OH > LLE, +30%, P < 0.10) and was on average 24% higher in women versus men. Similarly, basal adaptor expression was not influenced (P > 0.05) by age or LLE in women but was on average 26% higher (myeloid differentiation primary response 88, Myd88) and 23% lower [Toll interleukin (IL)-1 receptor-containing adaptor-inducing interferon-γ, TRIF] in women versus men. RE-induced changes in women, independent of the group, in TLR3, TLR4, TLR6 (∼2.1-fold, P < 0.05), Myd88 (∼1.2-fold, P < 0.10), and IκBα (∼0.3-fold, P < 0.05). Although there were some similar RE responses in men (TLR4: 2.1-fold, Myd88: 1.2-fold, IκBα: 0.4-fold), several components responded only in men to RE (TLR1, TLR8, TRIF, and IKKβ). Our findings support the sexual dimorphism of immunity, with women having greater basal skeletal muscle TLR expression and differential response to unaccustomed exercise than men.NEW & NOTEWORTHY We recently reported that aging increases basal expression of many Toll-like receptors (TLRs) in men and lifelong aerobic exercise does not prevent this effect. In addition, a resistance exercise (RE) challenge increased the expression of many TLRs. Here we show that basal TLR expression is minimally influenced by aging in women and findings support the sexual dimorphism of immunity, with women having greater basal skeletal muscle TLR expression and a differential response to unaccustomed exercise than men.

Exploring TLR signaling pathways as promising targets in cervical cancer: The road less traveled

Cervical cancer is the leading cause of cancer-related deaths for women globally. Despite notable advancements in prevention and treatment, the identification of novel therapeutic targets remains crucial for cervical cancer. Toll-like receptors (TLRs) play an essential role in innate immunity as pattern-recognition receptors. There are several types of pathogen-associated molecular patterns (PAMPs), including those present in cervical cancer cells, which have the ability to activate toll-like receptors (TLRs). Recent studies have revealed dysregulated toll-like receptor (TLR) signaling pathways in cervical cancer, leading to the production of inflammatory cytokines and chemokines that can facilitate tumor growth and metastasis. Consequently, TLRs hold significant promise as potential targets for innovative therapeutic agents against cervical cancer. This book chapter explores the role of TLR signaling pathways in cervical cancer, highlighting their potential for targeted therapy while addressing challenges such as tumor heterogeneity and off-target effects. Despite these obstacles, targeting TLR signaling pathways presents a promising approach for the development of novel and effective treatments for cervical cancer.

Riding the wave of innovation: immunoinformatics in fish disease control

The spread of infectious illnesses has been a significant factor restricting aquaculture production. To maximise aquatic animal health, vaccination tactics are very successful and cost-efficient for protecting fish and aquaculture animals against many disease pathogens. However, due to the increasing number of immunological cases and their complexity, it is impossible to manage, analyse, visualise, and interpret such data without the assistance of advanced computational techniques. Hence, the use of immunoinformatics tools is crucial, as they not only facilitate the management of massive amounts of data but also greatly contribute to the creation of fresh hypotheses regarding immune responses. In recent years, advances in biotechnology and immunoinformatics have opened up new research avenues for generating novel vaccines and enhancing existing vaccinations against outbreaks of infectious illnesses, thereby reducing aquaculture losses. This review focuses on understanding in silico epitope-based vaccine design, the creation of multi-epitope vaccines, the molecular interaction of immunogenic vaccines, and the application of immunoinformatics in fish disease based on the frequency of their application and reliable results. It is believed that it can bridge the gap between experimental and computational approaches and reduce the need for experimental research, so that only wet laboratory testing integrated with in silico techniques may yield highly promising results and be useful for the development of vaccines for fish.

Disulfide-HMGB1 signals through TLR4 and TLR9 to induce inflammatory macrophages capable of innate-adaptive crosstalk in human liver transplantation

Ischemia-reperfusion injury (IRI) during orthotopic liver transplantation (OLT) contributes to graft rejection and poor clinical outcomes. The disulfide form of high mobility group box 1 (diS-HMGB1), an intracellular protein released during OLT-IRI, induces pro-inflammatory macrophages. How diS-HMGB1 differentiates human monocytes into macrophages capable of activating adaptive immunity remains unknown. We investigated if diS-HMGB1 binds toll-like receptor (TLR) 4 and TLR9 to differentiate monocytes into pro-inflammatory macrophages that activate adaptive immunity and promote graft injury and dysfunction. Assessment of 106 clinical liver tissue and longitudinal blood samples revealed that OLT recipients were more likely to experience IRI and graft dysfunction with increased diS-HMGB1 released during reperfusion. Increased diS-HMGB1 concentration also correlated with TLR4/TLR9 activation, polarization of monocytes into pro-inflammatory macrophages, and production of anti-donor antibodies. In vitro, healthy volunteer monocytes stimulated with purified diS-HMGB1 had increased inflammatory cytokine secretion, antigen presentation machinery, and reactive oxygen species production. TLR4 inhibition primarily impeded cytokine/chemokine and costimulatory molecule programs, whereas TLR9 inhibition decreased HLA-DR and reactive oxygen species production. diS-HMGB1-polarized macrophages also showed increased capacity to present antigens and activate T memory cells. In murine OLT, diS-HMGB1 treatment potentiated ischemia-reperfusion-mediated hepatocellular injury, accompanied by increased serum alanine transaminase levels. This translational study identifies the diS-HMGB1/TLR4/TLR9 axis as potential therapeutic targets in OLT-IRI recipients.

Enhanced intra-articular therapy for rheumatoid arthritis using click-crosslinked hyaluronic acid hydrogels loaded with toll-like receptor antagonizing peptides

Rheumatoid arthritis (RA) is a chronic inflammatory disorder that results in the deterioration of joint cartilage and bone. Toll-like receptor 4 (TLR4) has been pinpointed as a key factor in RA-related inflammation. While Toll-like receptor antagonizing peptide 2 (TAP2) holds potential as an anti-inflammatory agent, its in vivo degradation rate hinders its efficacy. We engineered depots of TAP2 encapsulated in click-crosslinked hyaluronic acid (TAP2+Cx-HA) for intra-articular administration, aiming to enhance the effectiveness of TAP2 as an anti-inflammatory agent within the joint cavity. Our data demonstrated that FI-TAP2+Cx-HA achieves a longer retention time in the joint cavity compared to FI-TAP2 alone. Mechanistically, we found that TAP2 interacts with TLR4 on the cell membranes of inflammatory cells, thereby inhibiting the nuclear translocation of NF-κB and maintaining it in an inactive cytoplasmic state. In a rat model of RA, the TAP2+Cx-HA formulation effectively downregulated the inflammatory cytokines TNF-α and IL-6, while upregulating the anti-inflammatory cytokine IL-10 and the therapeutic protein 14-3-3ζ. This led to a more rapid restoration of cartilage thickness, increased deposition of glycosaminoglycans, and new bone tissue formation in the regenerated cartilage, in comparison to a single TAP2 treatment after a six-week period. Our results suggest that TAP2+Cx-HA could serve as a potent intra-articular treatment for RA, offering both symptomatic relief and promoting cartilage regeneration. This innovative delivery system holds significant promise for improving the management of RA and other inflammatory joint conditions. STATEMENT OF SIGNIFICANCE: In this study, we developed a therapy by creating toll-like receptor 4 (TLR4)-antagonizing peptide (TAP2)-loaded click-crosslinked hyaluronic acid (TAP2+Cx-HA) depots for direct intra-articular injection. Our study demonstrates that FI-TAP2+Cx-HA exhibits a more than threefold longer lifetime in the joint cavity compared to FI-TAP2 alone. Furthermore, we found that TAP2 binds to TLR4 and masks the nuclear localization signals of NF-κB, leading to its sequestration in an inactive state in the cytoplasm. In a rat model of RA, TAP2+Cx-HA effectively suppresses inflammatory molecules, specifically TNF-α and IL-6, while upregulating the anti-inflammatory cytokine IL-10 and the therapeutic protein 14-3-3ζ. This resulted in faster regeneration of cartilage thickness, increased glycosaminoglycan deposits in the regenerated cartilage, and a twofold increase in new bone tissue formation compared to a single TAP2 treatment.

Alterations of Plasma Biochemical and Immunological Parameters and Spatiotemporal Expression of TLR2 and TLR9 in Gibel Carp (Carassius auratus gibelio) after CyHV-2 Infection

Cyprinid herpesvirus II (CyHV-2), a highly contagious pathogen of gibel carp (Carassius auratus gibelio), causes herpesviral hematopoietic necrosis disease (HVHND) and enormous financial losses. However, there is limited information available regarding the changes in plasma biochemical and immunological parameters and the response characteristics of Toll-like receptor 2 (TLR2) and Toll-like receptor 9 (TLR9) in gibel carp after CyHV-2 infection. To address this knowledge gap, a sub-lethal CyHV-2 infection was conducted in gibel carp, and the sample was collected daily from 1 to 7 days post infection. The plasma biochemical analyses showed significant decreases in the content of glucose, total cholesterol (TCHO), and total protein (TP), along with marked increases in the level of uric acid, urea, creatinine (CREA), Complement 3 (C3), immunoglobulin D (IgD), and immunoglobulin M (IgM) as well as in the activity of alanine aminotransferase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), and lactate dehydrogenase (LDH) in the infected group. Compared with the control group, the concentration of cortisol, triglyceride (TG), and Complement 4 (C4) had no noticeable alterations in the infected group. Real-time quantitative PCR analysis showed significant upregulation of TLR2 and TLR9 mRNA expression in the spleen, kidney, brain, liver, intestine, and gill post CyHV-2 infection. Interestingly, a time- and tissue-dependent expression profile has been comparatively observed for TLR2 and TLR9 in the above tissues of gibel carp after CyHV-2 infection, suggesting distinct roles between TLR2 and TLR9 in antiviral response to CyHV-2 infection. Overall, our results demonstrated that CyHV-2 infection led to the disruption of the physiological metabolic process and damage to the liver and kidney, and induced different spatiotemporal expression patterns of TLR2 and TLR9, ultimately stimulating antiviral response via innate and adaptive immune system. These findings may provide a deeper understanding of the host immunity response to CyHV-2 infection and offer novel perspectives for the prevention and treatment and therapeutic drug development against CyHV-2.

Activation of Toll-like receptor 3 inhibits HIV infection of human iPSC-derived microglia

As a key immune cell in the brain, microglia are essential for protecting the central nervous system (CNS) from viral infections, including HIV. Microglia possess functional Toll-like receptor 3 (TLR3), a key viral sensor for activating interferon (IFN) signaling pathway-mediated antiviral immunity. We, therefore, studied the effect of poly (I:C), a synthetic ligand of TLR3, on the activation of the intracellular innate immunity against HIV in human iPSC-derived microglia (iMg). We found that poly (I:C) treatment of iMg effectively inhibits HIV infection/replication at both mRNA and protein levels. Investigations of the mechanisms revealed that TLR3 activation of iMg by poly (I:C) induced the expression of both type I and type III IFNs. Compared with untreated cells, the poly (I:C)-treated iMg expressed significantly higher levels of IFN-stimulated genes (ISGs) with known anti-HIV activities (ISG15, MxB, Viperin, MxA, and OAS-1). In addition, TLR3 activation elicited the expression of the HIV entry coreceptor CCR5 ligands (CC chemokines) in iMg. Furthermore, the transcriptional profile analysis showed that poly (I:C)-treated cells had the upregulated IFN signaling genes (ISG15, ISG20, IFITM1, IFITM2, IFITM3, IFITM10, APOBEC3A, OAS-2, MxA, and MxB) and the increased CC chemokine signaling genes (CCL1, CCL2, CCL3, CCL4, and CCL15). These observations indicate that TLR3 is a potential therapy target for activating the intracellular innate immunity against HIV infection/replication in human microglial cells. Therefore, further studies with animal models and clinical specimens are necessary to determine the role of TLR3 activation-driven antiviral response in the control and elimination of HIV in infected host cells.

NETosis: an emerging therapeutic target in renal diseases

Introduction

Neutrophil extracellular traps (NETs) are web-like structures composed of nuclear and granular components. The primary role of NETS is to prevent the dissemination of microbes and facilitate their elimination. However, this process is accompanied by collateral proinflammatory adverse effects when the NET release becomes uncontrollable, or clearance is impaired. Although NET-induced organ damage is conducted primarily and indirectly via immune complexes and the subsequent release of cytokines, their direct effects on cells are also remarkable. NETosis plays a critical pathogenic role in several renal disorders, such as the early phase of acute tubular necrosis, anti-neutrophil cytoplasmic antibody-mediated renal vasculitis, lupus nephritis, thrombotic microangiopathies, anti-glomerular basement membrane disease, and diabetic nephropathy. Their substantial contribution in the course of these disorders makes them a desirable target in the therapeutic armamentarium. This article gives an in-depth review of the heterogeneous pathogenesis and physiological regulations of NETosis and its pivotal role in renal diseases. Based on the pathogenesis, the article also outlines the current therapeutic options and possible molecular targets in the treatment of NET-related renal disorders.

Methods

We carried out thorough literature research published in PubMed and Google Scholar, including a comprehensive review and analysis of the classification, pathomechanisms, and a broad spectrum of NET-related kidney disorders.

Conclusions

NETosis plays a pivotal role in certain renal diseases. It initiates and maintains inflammatory and autoimmune disorders, thus making it a desirable target for improving patient and renal outcomes. Better understanding and clinical translation of the pathogenesis are crucial aspects to treatment, for improving patient, and renal outcomes.

Toll-like Receptor Agonists Are Unlikely to Provide Benefits in Head and Neck Squamous Cell Carcinoma: A Systematic Review and Meta-Analysis

BACKGROUND

Recurrent and metastatic (R/M) head and neck squamous cell carcinoma (HNSCC) has poor survival rates. Immunotherapy is the standard of care for R/M HNSCC, but objective responses occur in a minority of patients. Toll-like receptor (TLR) agonists promote antitumor immune responses and have been explored in clinical trials.

METHODS

A search for clinical trials using TLR agonists in HNSCC was performed under PRISMA guidelines. Data on patient characteristics, safety, and efficacy were collected and analyzed.

RESULTS

Three phase 1b trials with 40 patients and three phase 2 trials with 352 patients studying TLR8 and TLR9 agonists in combination with other treatment regimens for HNSCC were included. In phase 2 trials, there was no significant change in the objective response rate (RR = 1.13, CI 0.80-1.60) or association with increased grade 3+ adverse events (RR = 0.91, CI 0.76-1.11) associated with TLR agonist use.

CONCLUSION

TLR agonists do not appear to provide additional clinical benefits or increase adverse events in the treatment of HNSCC. Given these results across multiple clinical trials and drug regimens, it is unlikely that additional trials of TLR agonists will demonstrate clinical benefits in HNSCC.

Liposomal co-delivery of toll-like receptors 3 and 7 agonists induce a hot triple-negative breast cancer immune environment

Triple-negative breast cancer (TNBC) is highly aggressive and has no standard treatment. Although being considered as an alternative to conventional treatments for TNBC, immunotherapy has to deal with many challenges that hinder its efficacy, particularly the poor immunogenic condition of the tumor microenvironment (TME). Herein, we designed a liposomal nanoparticle (LN) platform that delivers simultaneously toll-like receptor 7 (imiquimod, IQ) and toll-like receptor 3 (poly(I:C), IC) agonists to take advantage of the different toll-like receptor (TLR) signaling pathways, which enhances the condition of TME from a "cold" to a "hot" immunogenic state. The optimized IQ/IC-loaded LN (IQ/IC-LN) was effectively internalized by cancer cells, macrophages, and dendritic cells, followed by the release of the delivered drugs and subsequent stimulation of the TLR3 and TLR7 signaling pathways. This stimulation encouraged the secretion of type I interferon (IFN-α, IFN-β) and CXCLl0, a T-cell and antigen-presenting cells (APCs) recruitment chemokine, from both cancer cells and macrophages and polarized macrophages to the M1 subtype in in vitro studies. Notably, systemic administration of IQ/IC-LN allowed for the high accumulation of drug content in the tumor, followed by the effective uptake by immune cells in the TME. IQ/IC-LN treatment comprehensively enhanced the immunogenic condition in the TME, which robustly inhibited tumor growth in tumor-bearing mice. Furthermore, synergistic antitumor efficacy was obtained when the IQ/IC-LN-induced immunogenic state in TME was combined with anti-PD1 antibody therapy. Thus, our results suggest the potential of combining 2 TLR agonists to reform the TME from a "cold" to a "hot" state, supporting the therapeutic efficacy of immune checkpoint inhibitors.

Interplay of Chemokines Receptors, Toll-like Receptors, and Host Immunological Pathways

A comprehensive framework has been established for understanding immunological pathways, which can be categorized into eradicated and tolerable immune responses. Toll-like receptors (TLRs) are associated with specific immune responses. TH1 immunity is related to TLR7, TLR8, and TLR9, while TH2 immunity is associated with TLR1, TLR2, and TLR6. TH22 immunity is linked to TLR2, TLR4, and TLR5, and THαβ (Tr1) immunity is related to TLR3, TLR7, and TLR9. The chemokine receptor CXCR5 is a marker of follicular helper T cells, and other chemokine receptors can also be classified within a framework based on host immunological pathways. On the basis of a literature review on chemokines and immunological pathways, the following associations were identified: CCR5 with TH1 responses, CCR1 with TH1-like responses, CCR4 (basophils) and CCR3 (eosinophils) with TH2 and TH9 responses, CCR10 with TH22 responses, CCR6 with TH17 responses, CXCR3 with THαβ responses, CCR8 with regulatory T cells (Treg), and CCR2 with TH3 responses. These findings contribute to the identification of biomarkers for immune cells and provide insights into host immunological pathways. Understanding the chemokine and Toll-like receptor system is crucial for comprehending the function of the innate immune system, as well as adaptive immune responses.

Adjuvant physiochemistry and advanced nanotechnology for vaccine development

Vaccines comprising innovative adjuvants are rapidly reaching advanced translational stages, such as the authorized nanotechnology adjuvants in mRNA vaccines against COVID-19 worldwide, offering new strategies to effectively combat diseases threatening human health. Adjuvants are vital ingredients in vaccines, which can augment the degree, extensiveness, and longevity of antigen specific immune response. The advances in the modulation of physicochemical properties of nanoplatforms elevate the capability of adjuvants in initiating the innate immune system and adaptive immunity, offering immense potential for developing vaccines against hard-to-target infectious diseases and cancer. In this review, we provide an essential introduction of the basic principles of prophylactic and therapeutic vaccination, key roles of adjuvants in augmenting and shaping immunity to achieve desired outcomes and effectiveness, and the physiochemical properties and action mechanisms of clinically approved adjuvants for humans. We particularly focus on the preclinical and clinical progress of highly immunogenic emerging nanotechnology adjuvants formulated in vaccines for cancer treatment or infectious disease prevention. We deliberate on how the immune system can sense and respond to the physicochemical cues (e.g., chirality, deformability, solubility, topology, and chemical structures) of nanotechnology adjuvants incorporated in the vaccines. Finally, we propose possible strategies to accelerate the clinical implementation of nanotechnology adjuvanted vaccines, such as in-depth elucidation of nano-immuno interactions, antigen identification and optimization by the deployment of high-dimensional multiomics analysis approaches, encouraging close collaborations among scientists from different scientific disciplines and aggressive exploration of novel nanotechnologies.

Regulation of IFNβ expression: focusing on the role of its promoter and transcription regulators

IFNβ is a single-copy gene without an intron. Under normal circumstances, it shows low or no expression in cells. It is upregulated only when the body needs it or is stimulated. Stimuli bind to the pattern recognition receptors (PRRs) and pass via various signaling pathways to several basic transcriptional regulators, such as IRFs, NF-кB, and AP-1. Subsequently, the transcriptional regulators enter the nucleus and bind to regulatory elements of the IFNβ promoter. After various modifications, the position of the nucleosome is altered and the complex is assembled to activate the IFNβ expression. However, IFNβ regulation involves a complex network. For the study of immunity and diseases, it is important to understand how transcription factors bind to regulatory elements through specific forms, which elements in cells are involved in regulation, what regulation occurs during the assembly of enhancers and transcription complexes, and the possible regulatory mechanisms after transcription. Thus, this review focuses on the various regulatory mechanisms and elements involved in the activation of IFNβ expression. In addition, we discuss the impact of this regulation in biology.

Pathomorphological Manifestations and the Course of the Cervical Cancer Disease Determined by Variations in the TLR4 Gene

Cervical cancer (CC) is often associated with human papillomavirus (HPV). Chronic inflammation has been described as one of the triggers of cancer. The immune system fights diseases, including cancer. The genetic polymorphism of pathogen recognition receptors potentially influences the infectious process, development, and disease progression. Many candidate genes SNPs have been contradictory demonstrated to be associated with cervical cancer by association studies, GWAS. TLR4 gene activation can promote antitumor immunity. It can also result in immunosuppression and tumor growth. Our study aimed to investigate eight selected polymorphisms of the TLR4 gene (rs10759932, rs1927906, rs11536898, rs11536865, rs10983755, rs4986790, rs4986791, rs11536897) and to determine the impact of polymorphisms in genotypes and alleles on the pathomorphological characteristics and progression in a group of 172 cervical cancer subjects with stage I-IV. Genotyping was performed by RT-PCR assay. We detected that the CA genotype and A allele of rs11536898 were significantly more frequent in patients with metastases (p = 0.026; p = 0.008). The multivariate logistic regression analysis confirmed this link to be significant. The effect of rs10759932 and rs11536898 on progression-free survival (PFS) and overall survival (OS) has been identified as important. In univariate and multivariate Cox analyses, AA genotype of rs11536898 was a negative prognostic factor for PFS (p = 0.024; p = 0.057, respectively) and OS (p = 0.008; p = 0.042, respectively). Rs11536898 C allele predisposed for longer PFS (univariate and multivariate: p = 0.025; p = 0.048, respectively) and for better OS (univariate and multivariate: p = 0.010; p = 0.043). The worse prognostic factor of rs10759932 in a univariate and multivariate Cox analysis for survival was CC genotype: shorter PFS (p = 0.032) and increased risk of death (p = 0.048; p = 0.015, respectively). The T allele of rs10759932 increased longer PFS (univariate and multivariate: p = 0.048; p = 0.019, respectively) and longer OS (univariate and multivariate: p = 0.037; p = 0.009, respectively). Our study suggests that SNPs rs10759932 and rs11536898 may have the potential to be markers contributing to the assessment of the cervical cancer prognosis. Further studies, preferably with larger groups of different ethnic backgrounds, are needed to confirm the results of the current study.

Intraperitoneal metastasis of ovarian cancer: new insights on resident macrophages in the peritoneal cavity

Ovarian cancer metastasis occurs primarily in the peritoneal cavity. Orchestration of cancer cells with various cell types, particularly macrophages, in the peritoneal cavity creates a metastasis-favorable environment. In the past decade, macrophage heterogeneities in different organs as well as their diverse roles in tumor settings have been an emerging field. This review highlights the unique microenvironment of the peritoneal cavity, consisting of the peritoneal fluid, peritoneum, and omentum, as well as their own resident macrophage populations. Contributions of resident macrophages in ovarian cancer metastasis are summarized; potential therapeutic strategies by targeting such cells are discussed. A better understanding of the immunological microenvironment in the peritoneal cavity will provide a stepping-stone to new strategies for developing macrophage-based therapies and is a key step toward the unattainable eradication of intraperitoneal metastasis of ovarian cancer.

Toll-Like Receptors and the Response to Radiotherapy in Solid Tumors: Challenges and Opportunities

Toll-like receptors (TLRs) are indispensable for the activation, maintenance and halting of immune responses. TLRs can mediate inflammation by recognizing molecular patterns in microbes (pathogen-associated molecular patterns: PAMPs) and endogenous ligands (danger-associated molecular patterns: DAMPs) released by injured or dead cells. For this reason, TLR ligands have attracted much attention in recent years in many cancer vaccines, alone or in combination with immunotherapy, chemotherapy and radiotherapy (RT). TLRs have been shown to play controversial roles in cancer, depending on various factors that can mediate tumor progression or apoptosis. Several TLR agonists have reached clinical trials and are being evaluated in combination with standard of care therapies, including RT. Despite their prolific and central role in mediating immune responses, the role of TLRs in cancer, particularly in response to radiation, remains poorly understood. Radiation is recognized as either a direct stimulant of TLR pathways, or indirectly through the damage it causes to target cells that subsequently activate TLRs. These effects can mediate pro-tumoral and anti-tumoral effects depending on various factors such as radiation dose and fractionation, as well as host genomic features. In this review, we examine how TLR signaling affects tumor response to RT, and we provide a framework for the design of TLR-based therapies with RT.

Emerging treatments for myelodysplastic syndromes: Biological rationales and clinical translation

Myelodysplastic syndromes (MDSs) are a heterogeneous group of clonal hematopoietic stem cell disorders characterized by myeloid dysplasia, peripheral blood cytopenias, and increased risk of progression to acute myeloid leukemia (AML). The standard of care for patients with MDS is hypomethylating agent (HMA)-based therapy; however, nearly 50% of patients have no response to the treatment. Patients with MDS in whom HMA therapy has failed have a dismal prognosis and no approved second-line therapy options, so enrollment in clinical trials of experimental agents represents these patients' only chance for improved outcomes. A better understanding of the molecular and biological mechanisms underpinning MDS pathogenesis has enabled the development of new agents that target molecular alterations, cell death regulators, signaling pathways, and immune regulatory proteins in MDS. Here, we review novel therapies for patients with MDS in whom HMA therapy has failed, with an emphasis on the biological rationale for these therapies' development.

Effect of CpG-Oligonucleotide in Enhancing Recombinant Herpes Virus of Turkey-Laryngotracheitis Vaccine-Induced Immune Responses in One-Day-Old Broiler Chickens

Infectious laryngotracheitis (ILT) is an economically important disease of chickens. While the recombinant vaccines can reduce clinical disease severity, the associated drawbacks are poor immunogenicity and delayed onset of immunity. Here, we used CpG-oligonucleotides (ODN) as an in ovo adjuvant in boosting recombinant herpesvirus of turkey-laryngotracheitis (rHVT-LT) vaccine-induced responses in one-day-old broiler chickens. Two CpG-ODN doses (5 and 10 μg/egg) with no adverse effect on the vaccine-virus replication or chick hatchability were selected for immune-response evaluation. Results showed that while CpG-ODN adjuvantation induced an increased transcription of splenic IFNγ and IL-1β, and lung IFNγ genes, the IL-1β gene expression in the lung was significantly downregulated compared to the control. Additionally, the transcription of toll-like receptor (TLR)21 in the spleen and lung and inducible nitric oxide synthase (iNOS) in the spleen of all vaccinated groups was significantly reduced. Furthermore, splenic cellular immunophenotyping showed that the CpG-ODN-10μg adjuvanted vaccination induced a significantly higher number of macrophages, TCRγδ+, and CD4+ T cells as well as a higher frequency of activated T cells (CD4+CD44+) when compared to the control. Collectively, the findings suggested that CpG-ODN can boost rHVT-LT-induced immune responses in day-old chicks, which may help in anti-ILT defense during their later stages of life.

The Role of TRL7/8 Agonists in Cancer Therapy, with Special Emphasis on Hematologic Malignancies

Toll-like receptors (TLR) belong to the pattern recognition receptors (PRR). TLR7 and the closely correlated TLR8 affiliate with toll-like receptors family, are located in endosomes. They recognize single-stranded ribonucleic acid (RNA) molecules and synthetic deoxyribonucleic acid (DNA)/RNA analogs-oligoribonucleotides. TLRs are primarily expressed in hematopoietic cells. There is compiling evidence implying that TLRs also direct the formation of blood cellular components and make a contribution to the pathogenesis of certain hematopoietic malignancies. The latest research shows a positive effect of therapy with TRL agonists on the course of hemato-oncological diseases. Ligands impact activation of antigen-presenting cells which results in production of cytokines, transfer of mentioned cells to the lymphoid tissue and co-stimulatory surface molecules expression required for T-cell activation. Toll-like receptor agonists have already been used in oncology especially in the treatment of dermatological neoplastic lesions. The usage of these substances in the treatment of solid tumors is being investigated. The present review discusses the direct and indirect influence that TLR7/8 agonists, such as imiquimod, imidazoquinolines and resiquimod have on neoplastic cells and their promising role as adjuvants in anticancer vaccines.

Innate Immune Program in Formation of Tumor-Initiating Cells from Cells-of-Origin of Breast, Prostate, and Ovarian Cancers

Tumor-initiating cells (TICs), also known as cancer stem cells (CSCs), are cancer cells that can initiate a tumor, possess self-renewal capacity, and can contribute to tumor heterogeneity. TICs/CSCs are developed from their cells-of-origin. In breast, prostate, and ovarian cancers, progenitor cells for mammary alveolar cells, prostate luminal (secretory) cells, and fallopian tube secretory cells are the preferred cellular origins for their corresponding cancer types. These luminal progenitors (LPs) express common innate immune program (e.g., Toll-like receptor (TLR) signaling)-related genes. Microbes such as bacteria are now found in breast, prostate, and fallopian tube tissues and their corresponding cancer types, raising the possibility that their LPs may sense the presence of microbes and trigger their innate immune/TLR pathways, leading to an inflammatory microenvironment. Crosstalk between immune cells (e.g., macrophages) and affected epithelial cells (e.g., LPs) may eventually contribute to formation of TICs/CSCs from their corresponding LPs, in part via STAT3 and/or NFκB pathways. As such, TICs/CSCs can inherit expression of innate-immunity/TLR-pathway-related genes from their cells-of-origin; the innate immune program may also represent their unique vulnerability, which can be explored therapeutically (e.g., by enhancing immunotherapy via augmenting TLR signaling).

A Review of Bullous Dermatologic Adverse Events Associated with Anti-Cancer Therapy

The rapid evolution of anti-cancer therapy (including chemotherapy, targeted therapy, and immunotherapy) in recent years has led to a more favorable efficacy and safety profile for a growing cancer population, and the improvement of overall survival and reduction of morbidity for many cancers. Anti-cancer therapy improves outcomes for cancer patients; however, many classes of anti-cancer therapy have been implicated in the induction of bullous dermatologic adverse events (DAE), leading to reduced patient quality of life and in some cases discontinuation of life-prolonging or palliative therapy. Timely and effective management of adverse events is critical for reducing treatment interruptions and preserving an anti-tumor effect. Bullous DAE may be limited to the skin or have systemic involvement with greater risk of morbidity and mortality. We present the epidemiology, diagnosis, pathogenesis, and management of bullous DAE secondary to anti-cancer therapies to enable clinicians to optimize management for these patients.

Association analysis between the TLR9 gene polymorphism rs352140 and type 1 diabetes

Background

To a great extent, genetic factors contribute to the susceptibility to type 1 diabetes (T1D) development, and by triggering immune imbalance, Toll-like receptor (TLR) 9 is involved in the development of T1D. However, there is a lack of evidence supporting a genetic association between polymorphisms in the TLR9 gene and T1D.

Methods

In total, 1513 individuals, including T1D patients (n=738) and healthy control individuals (n=775), from the Han Chinese population were recruited for an association analysis of the rs352140 polymorphism of the TLR9 gene and T1D. rs352140 was genotyped by MassARRAY. The allele and genotype distributions of rs352140 in the T1D and healthy groups and those in different T1D subgroups were analyzed by the chi-squared test and binary logistic regression model. The chi-square test and Kruskal-Wallis H test were performed to explore the association between genotype and phenotype in T1D patients.

Results

The allele and genotype distributions of rs352140 were significantly different in T1D patients and healthy control individuals (p=0.019, p=0.035). Specifically, the T allele and TT genotype of rs352140 conferred a higher risk of T1D (OR=1.194, 95% CI=1.029-1.385, p=0.019, OR=1.535, 95% CI=1.108-2.126, p=0.010). The allele and genotype distributions of rs352140 were not significantly different between childhood-onset and adult-onset T1D and between T1D with a single islet autoantibody and T1D with multiple islet autoantibodies (p=0.603, p=0.743). rs352140 was associated with T1D susceptibility according to the recessive and additive models (p=0.015, p=0.019) but was not associated with T1D susceptibility in the dominant and overdominant models (p=0.117, p=0.928). Moreover, genotype-phenotype association analysis showed that the TT genotype of rs352140 was associated with higher fasting C-peptide levels (p=0.017).

Conclusion

In the Han Chinese population, the TLR9 polymorphism rs352140 is associated with T1D and is a risk factor for susceptibility to T1D.

Toll-like receptors in cardiac hypertrophy

Toll-like receptors (TLRs) are a family of pattern recognition receptors (PRRs) that can identify pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs). TLRs play an important role in the innate immune response, leading to acute and chronic inflammation. Cardiac hypertrophy, an important cardiac remodeling phenotype during cardiovascular disease, contributes to the development of heart failure. In previous decades, many studies have reported that TLR-mediated inflammation was involved in the induction of myocardium hypertrophic remodeling, suggesting that targeting TLR signaling might be an effective strategy against pathological cardiac hypertrophy. Thus, it is necessary to study the mechanisms underlying TLR functions in cardiac hypertrophy. In this review, we summarized key findings of TLR signaling in cardiac hypertrophy.

Toll-like receptors and NLRP3 inflammasome-dependent pathways in Parkinson's disease: mechanisms and therapeutic implications

Parkinson's disease (PD) is a chronic progressive neurodegenerative disorder characterized by motor and non-motor disturbances as a result of a complex and not fully understood pathogenesis, probably including neuroinflammation, oxidative stress, and formation of alpha-synuclein (α-syn) aggregates. As age is the main risk factor for several neurodegenerative disorders including PD, progressive aging of the immune system leading to inflammaging and immunosenescence may contribute to neuroinflammation leading to PD onset and progression; abnormal α-syn aggregation in the context of immune dysfunction may favor activation of nucleotide-binding oligomerization domain-like receptor (NOD) family pyrin domain containing 3 (NLRP3) inflammasome within microglial cells through interaction with toll-like receptors (TLRs). This process would further lead to activation of Caspase (Cas)-1, and increased production of pro-inflammatory cytokines (PC), with subsequent impairment of mitochondria and damage to dopaminergic neurons. All these phenomena are mediated by the translocation of nuclear factor kappa-B (NF-κB) and enhanced by reactive oxygen species (ROS). To date, drugs to treat PD are mainly aimed at relieving clinical symptoms and there are no disease-modifying options to reverse or stop disease progression. This review outlines the role of the TLR/NLRP3/Cas-1 pathway in PD-related immune dysfunction, also focusing on specific therapeutic options that might be used since the early stages of the disease to counteract neuroinflammation and immune dysfunction.

Modeling of Transmembrane Domain and Full-Length TLRs in Membrane Models

Toll-like receptors (TLRs), classified as pattern recognition receptors, have a primordial role in the activation of the innate immunity. In particular, TLR4 binds to lipopolysaccharides (LPS), a membrane constituent of Gram-negative bacteria, and, together with Myeloid Differentiation factor 2 (MD-2) protein, forms a heterodimeric complex which leads to the activation of the innate immune system response. Identification of TLRs has sparked great interest in the therapeutic manipulation of the innate immune system. In particular, TLR4 antagonists may be useful for the treatment of septic shock, certain autoimmune diseases, noninfectious inflammatory disorders, and neuropathic pain, and TLR4 agonists are under development as vaccine adjuvants in antitumoral treatments. Therefore, TLR4 has risen as a promising therapeutic target, and its modulation constitutes a highly relevant and active research area. Deep structural understanding of TLR4 signaling may help in the design and discovery of TLR4-modulating molecules with desirable therapeutic properties.Computational studies of the different independent domains composing the TLR4 were undertaken, to understand the differential domain organization of TLR4 in aqueous and membrane environments, including Liquid-disordered (Ld) and Liquid-ordered (Lo) membrane models, to account for the TLR4 recruitment in lipid rafts over activation. We modeled, by means of all-atom Molecular Dynamics (MD) simulations, the structural assembly of plausible full-length TLR4 models embedded into a realistic plasma membrane, accounting for the active (agonist) state of the TLR4, thus providing an analysis at both atomic/molecular and thermodynamic levels of the TLR4 assembly and biological activity. Our results unveil relevant molecular aspects involved in the mechanism of receptor activation, and adaptor recruitment in the innate immune pathways, and will promote the discovery of new TLR4 modulators and probes.

Unrevealing the Role of TLRs in the Pathogenesis of Autoimmune Disease by Using Mouse Model of Diabetes

Toll-like receptors (TLRs) are receptors of the innate immune system specialized in recognizing conserved molecular pattern of pathogens and initiating an appropriate immune response. Along with the recognition of foreign materials, TLRs have also been shown to respond to endogenous molecules, thus mediating the development of autoimmune diseases. Type 1 diabetes (T1D) is a prototypic autoimmune disease in which TLRs play a pathogenic role. We here describe a protocol to study the role of TLRs in the development and progression of T1D by resorting to the nonobese diabetic (NOD) mouse model.

Identification of common molecular signatures of SARS-CoV-2 infection and its influence on acute kidney injury and chronic kidney disease

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the main cause of COVID-19, causing hundreds of millions of confirmed cases and more than 18.2 million deaths worldwide. Acute kidney injury (AKI) is a common complication of COVID-19 that leads to an increase in mortality, especially in intensive care unit (ICU) settings, and chronic kidney disease (CKD) is a high risk factor for COVID-19 and its related mortality. However, the underlying molecular mechanisms among AKI, CKD, and COVID-19 are unclear. Therefore, transcriptome analysis was performed to examine common pathways and molecular biomarkers for AKI, CKD, and COVID-19 in an attempt to understand the association of SARS-CoV-2 infection with AKI and CKD. Three RNA-seq datasets (GSE147507, GSE1563, and GSE66494) from the GEO database were used to detect differentially expressed genes (DEGs) for COVID-19 with AKI and CKD to search for shared pathways and candidate targets. A total of 17 common DEGs were confirmed, and their biological functions and signaling pathways were characterized by enrichment analysis. MAPK signaling, the structural pathway of interleukin 1 (IL-1), and the Toll-like receptor pathway appear to be involved in the occurrence of these diseases. Hub genes identified from the protein-protein interaction (PPI) network, including DUSP6, BHLHE40, RASGRP1, and TAB2, are potential therapeutic targets in COVID-19 with AKI and CKD. Common genes and pathways may play pathogenic roles in these three diseases mainly through the activation of immune inflammation. Networks of transcription factor (TF)-gene, miRNA-gene, and gene-disease interactions from the datasets were also constructed, and key gene regulators influencing the progression of these three diseases were further identified among the DEGs. Moreover, new drug targets were predicted based on these common DEGs, and molecular docking and molecular dynamics (MD) simulations were performed. Finally, a diagnostic model of COVID-19 was established based on these common DEGs. Taken together, the molecular and signaling pathways identified in this study may be related to the mechanisms by which SARS-CoV-2 infection affects renal function. These findings are significant for the effective treatment of COVID-19 in patients with kidney diseases.

Antimicrobial peptides could antagonize uncontrolled inflammation via Toll-like 4 receptor

Antimicrobial peptides are part of the organism's defense system. They are multifunctional molecules capable of modulating the host's immune system and recognizing molecules present in pathogens such as lipopolysaccharides (LPSs). LPSs are recognized by molecular patterns associated with pathogens known as Toll-like receptors (TLRs) that protect the organism from pathological microorganisms. TLR4 is responsible for LPS recognition, thus inducing an innate immune response. TLR4 hyperstimulation induces the uncontrolled inflammatory process that is observed in many illnesses, including neurodegenerative, autoimmune and psoriasis). Molecules that act on TLR4 can antagonize the exacerbated inflammatory process. In this context, antimicrobial peptides (AMPs) are promising molecules capable of mediating toll-like receptor signaling. Therefore, here we address the AMPs studied so far with the aim of inhibiting the intense inflammatory process. In addition, we aim to explore some of the interactions between exogenous AMPs and TLR4.