Discordant biological and toxicological species responses to TLR3 activation

An innate immune response to adeno-associated virus genomes decreases cortical dendritic complexity and disrupts synaptic transmission

Recombinant adeno-associated viruses (AAVs) allow rapid and efficient gene delivery to the nervous system, are widely used in neuroscience research, and are the basis of FDA-approved neuron-targeting gene therapies. Here we find that an innate immune response to the AAV genome reduces dendritic length and complexity and disrupts synaptic transmission in mouse somatosensory cortex. Dendritic loss is apparent 3 weeks after injection of experimentally relevant viral titers, is not restricted to a particular capsid serotype, transgene, promoter, or production facility, and cannot be explained by responses to surgery or transgene expression. AAV-associated dendritic loss is accompanied by a decrease in the frequency and amplitude of miniature excitatory postsynaptic currents and an increase in the proportion of GluA2-lacking, calcium-permeable AMPA receptors. The AAV genome is rich in unmethylated CpG DNA, which is recognized by the innate immunoreceptor Toll-like receptor 9 (TLR9), and acutely blocking TLR9 preserves dendritic complexity and AMPA receptor subunit composition in AAV-injected mice. These results reveal unexpected impacts of an immune response to the AAV genome on neuronal structure and function and identify approaches to improve the safety and efficacy of AAV-mediated gene delivery in the nervous system.

Advancing Research and Treatment: An Overview of Clinical Trials in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and Future Perspectives

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a chronic, debilitating, and multi-faceted illness. Heterogenous onset and clinical presentation with additional comorbidities make it difficult to diagnose, characterize, and successfully treat. Current treatment guidelines focus on symptom management, but with no clear target or causative mechanism, remission rates are low, and fewer than 5% of patients return to their pre-morbid activity levels. Therefore, there is an urgent need to undertake robust clinical trials to identify effective treatments. This review synthesizes insights from clinical trials exploring pharmacological interventions and dietary supplements targeting immunological, metabolic, gastrointestinal, neurological, and neuroendocrine dysfunction in ME/CFS patients which require further exploration. Additionally, the trialling of alternative interventions in ME/CFS based on reported efficacy in the treatment of illnesses with overlapping symptomology is also discussed. Finally, we provide important considerations and make recommendations, focusing on outcome measures, to ensure the execution of future high-quality clinical trials to establish clinical efficacy of evidence-based interventions that are needed for adoption in clinical practice.

Off target toxicities and links with physicochemical properties of medicinal products, including antibiotics, oligonucleotides, lipid nanoparticles (with cationic and/or anionic charges). Data review suggests an emerging pattern

Toxicology is an essential part of any drug development plan. Circumnavigating the risk of failure because of a toxicity issue can be a challenge, and failure in late development is extremely costly. To identify potential risks, it requires more than just understanding the biological target. The toxicologist needs to consider a compound's structure, it's physicochemical properties (including the impact of the overall formulation), as well as the biological target (e.g., receptor interactions). Understanding the impact of the physicochemical properties can be used to predict potential toxicities in advance by incorporating key endpoints in early screening strategies and/or used to compare toxicity profiles across lead candidates. This review discussed the risks of off-target and/or non-specific toxicities that may be associated with the physicochemical properties of compounds, especially those carrying dominant positive or negative charges, including amphiphilic small molecules, peptides, oligonucleotides and lipids/liposomes/lipid nanoparticles. The latter of which are being seen more and more in drug development, including the recent Covid pandemic, where mRNA and lipid nanoparticle technology is playing more of a role in vaccine development. The translation between non-clinical and clinical data is also considered, questioning how a physicochemical driven toxicity may be more universal across species, which means that such toxicity may be reassuringly translatable between species and as such, this information may also be considered as a support to the 3 R's, particularly in the early screening stages of a drug development plan.

Experimental drugs in randomized controlled trials for long-COVID: what's in the pipeline? A systematic and critical review

INTRODUCTION

Over three years have passed since the emergence of coronavirus disease 2019 (COVID-19), and yet the treatment for long-COVID, a post-COVID-19 syndrome, remains long overdue. Currently, there is no standardized treatment available for long-COVID, primarily due to the lack of funding for post-acute infection syndromes (PAIS). Nevertheless, the past few years have seen a renewed interest in long-COVID research, with billions of dollars allocated for this purpose. As a result, multiple randomized controlled trials (RCTs) have been funded in the quest to find an effective treatment for long-COVID.

AREAS COVERED

This systematic review identified and evaluated the potential of current drug treatments for long-COVID, examining both completed and ongoing RCTs.

EXPERT OPINION

We identified four completed and 22 ongoing RCTs, investigating 22 unique drugs. However, most drugs were deemed to not have high potential for treating long-COVID, according to three pre-specified domains, a testament to the ordeal of treating long-COVID. Given that long-COVID is highly multifaceted with several proposed subtypes, treatments likely need to be tailored accordingly. Currently, rintatolimod appears to have modest to high potential for treating the myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) subtype, LTY-100 and Treamid for pulmonary fibrosis subtype, and metformin for general long-COVID prevention.

In the SARS-CoV-2 Pandora Pandemic: Can the Stance of Premorbid Intestinal Innate Immune System as Measured by Fecal Adnab-9 Binding of p87:Blood Ferritin, Yielding the FERAD Ratio, Predict COVID-19 Susceptibility and Survival in a Prospective Population Database?

SARS-CoV-2 severity predictions are feasible, though individual susceptibility is not. The latter prediction allows for planning vaccination strategies and the quarantine of vulnerable targets. Ironically, the innate immune response (InImS) is both an antiviral defense and the potential cause of adverse immune outcomes. The competition for iron has been recognized between both the immune system and invading pathogens and expressed in a ratio of ferritin divided by p87 (as defined by the Adnab-9 ELISA stool-binding optical density, minus the background), known as the FERAD ratio. Associations with the FERAD ratio may allow predictive modeling for the susceptibility and severity of disease. We evaluated other potential COVID-19 biomarkers prospectively. Patients with PCR+ COVID-19 tests (Group 1; n = 28) were compared to three other groups. In Group 2 (n = 36), and 13 patients displayed COVID-19-like symptoms but had negative PCR or negative antibody tests. Group 3 (n = 90) had no symptoms and were negative when routinely PCR-tested before medical procedures. Group 4 (n = 2129) comprised a pool of patients who had stool tests and symptoms, but their COVID-19 diagnoses were unknown; therefore, they were chosen to represent the general population. Twenty percent of the Group 4 patients (n = 432) had sufficient data to calculate their FERAD ratios, which were inversely correlated with the risk of COVID-19 in the future. In a case report of a neonate, we studied three biomarkers implicated in COVID-19, including p87, Src (cellular-p60-sarcoma antigen), and Abl (ABL-proto-oncogene 2). The InImS of the first two were positively correlated. An inverse correlation was found between ferritin and lysozyme in serum (p < 0.05), suggesting that iron could have impaired an important innate immune system anti-viral effector and could partially explain future COVID-19 susceptibility.

Ebola virus disease: In vivo protection provided by the PAMP restricted TLR3 agonist rintatolimod and its mechanism of action

Ebola virus (EBOV) is a highly infectious and lethal pathogen responsible for sporadic self-limiting clusters of Ebola virus disease (EVD) in Central Africa capable of reaching epidemic status. 100% protection from lethal EBOV-Zaire in Balb/c mice was achieved by rintatolimod (Ampligen) at the well tolerated human clinical dose of 6 mg/kg. The data indicate that the mechanism of action is rintatolimod's dual ability to act as both a competitive decoy for the IID domain of VP35 blocking viral dsRNA sequestration and as a pathogen-associated molecular pattern (PAMP) restricted agonist for direct TLR3 activation but lacking RIG-1-like cytosolic helicase agonist properties. These data show promise for rintatolimod as a prophylactic therapy against human Ebola outbreaks.

Oligonucleotide-Based Therapies for Chronic HBV Infection: A Primer on Biochemistry, Mechanisms and Antiviral Effects

Three types of oligonucleotide-based medicines are under clinical development for the treatment of chronic HBV infection. Antisense oligonucleotides (ASOs) and synthetic interfering RNA (siRNA) are designed to degrade HBV mRNA, and nucleic acid polymers (NAPs) stop the assembly and secretion of HBV subviral particles. Extensive clinical development of ASOs and siRNA for a variety of liver diseases has established a solid understanding of their pharmacodynamics, accumulation in different tissue types in the liver, pharmacological effects, off-target effects and how chemical modifications and delivery approaches affect these parameters. These effects are highly conserved for all ASO and siRNA used in human studies to date. The clinical assessment of several ASO and siRNA compounds in chronic HBV infection in recent years is complicated by the different delivery approaches used. Moreover, these assessments have not considered the large clinical database of ASO/siRNA function in other liver diseases and known off target effects in other viral infections. The goal of this review is to summarize the current understanding of ASO/siRNA/NAP pharmacology and integrate these concepts into current clinical results for these compounds in the treatment of chronic HBV infection.

IL-1 and IL-1ra are key regulators of the inflammatory response to RNA vaccines

The use of lipid-formulated RNA vaccines for cancer or COVID-19 is associated with dose-limiting systemic inflammatory responses in humans that were not predicted from preclinical studies. Here, we show that the 'interleukin 1 (IL-1)-interleukin 1 receptor antagonist (IL-1ra)' axis regulates vaccine-mediated systemic inflammation in a host-specific manner. In human immune cells, RNA vaccines induce production of IL-1 cytokines, predominantly IL-1β, which is dependent on both the RNA and lipid formulation. IL-1 in turn triggers the induction of the broad spectrum of pro-inflammatory cytokines (including IL-6). Unlike humans, murine leukocytes respond to RNA vaccines by upregulating anti-inflammatory IL-1ra relative to IL-1 (predominantly IL-1α), protecting mice from cytokine-mediated toxicities at >1,000-fold higher vaccine doses. Thus, the IL-1 pathway plays a key role in triggering RNA vaccine-associated innate signaling, an effect that was unexpectedly amplified by certain lipids used in vaccine formulations incorporating N1-methyl-pseudouridine-modified RNA to reduce activation of Toll-like receptor signaling.

Myocarditis and COVID-19 mRNA vaccines: a mechanistic hypothesis involving dsRNA

While tolerance to COVID-19 vaccination is considered satisfactory, a phenomenon of myocarditis, although rare, is becoming a safety concern in mRNA COVID-19 vaccination. The presence of low residual levels of double-strand RNA (dsRNA) has been reported in mRNA COVID-19 vaccine preparations. dsRNA is a known inducer of immune-inflammatory reactions. dsRNA present in vaccine nanoparticles may be suspected to be at the origin of the still unexplained cases of myocarditis.

Adaptive Evolution in TRIF Leads to Discordance between Human and Mouse Innate Immune Signaling

The TIR domain-containing adapter inducing IFN-β (TRIF) protein is an innate immune system protein that mediates the MyD88-independent toll-like receptor response pathway in mice and humans. Previously, we identified positive selection at seven distinct residues in mouse TRIF (mTRIF), as compared with human and other mammalian orthologs, thus predicting protein functional shift in mTRIF. We reconstructed TRIF for the most recent common ancestor of mouse and human, and mutated this at the seven sites to their extant mouse/human states. We overexpressed these TRIF mutants in immortalized human and mouse cell lines and monitored TRIF-dependent cytokine production and gene expression induction. We show that optimal TRIF function in human and mouse is dependent on the identity of the positively selected sites. These data provide us with molecular data relating observed differences in response between mouse and human MyD88-independent signaling in the innate immune system with protein functional change.

Rintatolimod Induces Antiviral Activities in Human Pancreatic Cancer Cells: Opening for an Anti-COVID-19 Opportunity in Cancer Patients?

Simple Summary

Specific treatment for COVID-19 infections in cancer patients is lacking while the demand for treatment is increasing. Therefore, we explored the effect of Rintatolimod, a Toll-like receptor 3 (TLR3) agonist, on human epithelial cancerous cells. Our results demonstrated that Rintatolimod stimulated an anti-viral effect by producing RNase L that blocks virus replication. Moreover, Rintatolimod activated the innate and the adaptive immune systems by activating a cascade of actions in human cancerous cells. We believe that Rintatolimod should be considered in the treatment regimens of cancer patients who suffer from SARS-CoV-2 infection.

Abstract

Severe acute respiratory virus-2 (SARS-CoV-2) has spread globally leading to a devastating loss of life. Large registry studies have begun to shed light on the epidemiological and clinical vulnerabilities of cancer patients who succumb to or endure poor outcomes of SARS-CoV-2. Specific treatment for COVID-19 infections in cancer patients is lacking while the demand for treatment is increasing. Therefore, we explored the effect of Rintatolimod (Ampligen^®) (AIM ImmunoTech, Ocala, FL, USA), a Toll-like receptor 3 (TLR3) agonist, to treat uninfected human pancreatic cancer cells (HPACs). The direct effect of Rintatolimod was measured by targeted gene expression profiling and by proteomics measurements. Our results show that Rintatolimod induces an antiviral effect in HPACs by inducing RNase-L-dependent and independent pathways of the innate immune system. Treatment with Rintatolimod activated the interferon signaling pathway, leading to the overexpression of several cytokines and chemokines in epithelial cells. Furthermore, Rintatolimod treatment increased the expression of angiogenesis-related genes without promoting fibrosis, which is the main cause of death in patients with COVID-19. We conclude that Rintatolimod could be considered an early additional treatment option for cancer patients who are infected with SARS-CoV-2 to prevent the complicated severity of the disease.

Characterization, expression and function analysis of the TLR3 gene in golden pompano (Trachinotus ovatus)

Toll-like receptors (TLRs)are pattern recognition receptors (PRRs) that are important in invertebrate innate immunity for the recognition and elimination of pathogens. Although they were reported in many fishes, Toll-like receptors subfamily contain a large number of members with different functions that need to research in deep. In the present study, the full-length cDNA of TLR3 from the golden pompano, Trachinotus ovatus, was cloned and characterized. The full length of ToTLR3 cDNA was 3710 bp including an open reading frame of 2760 bp encoding a peptide of 919 amino acids. The derived amino acids sequence comprised of 14 leucine-rich repeats (LRR), capped with LRRCT followed by transmembrane domain and cytoplasmic Toll/IL-1R domain (TIR). Multiple sequence alignment and phylogenetic analysis revealed that ToTLR3 shared the highest similarity to the teleost fish and suggested ToTLR3 is fairly conservative in evolution process. Tissues distribution analysis indicated that ToTLR3 showed a tissue-specific variation with high expression in blood and liver. After the fish were stimulated by poly(I:C), flagellin and LPS, ToTLR3 expression in the liver, intestine, blood, kidney, skin and muscle was significantly upregulated in a time-depended manner, especially in immune related tissues such as liver, blood and kidney. Binding assay revealed the specificity of rToTLR3 for pathogen-associated molecular patterns (PAMPs) and bacteria that included Vibrio harveyi, V. vulnificus, V. anguillarum, Photobacterium damselae, Escherichia coli, Aeromonas hydrophila, Staphylococcus aureus and PolyI:C, LPS, Flagellin, and PGN. In addition, a luciferase reporter assay showed that overexpression ToTLR3 significantly increased NF-κB activity. Collectively, our results suggested that ToTLR3 might play an important role as a pattern recognition receptor (PRR) in the immune response towards pathogen infections, and transmiss the danger signal to downstream signaling pathways.

Immune-Stimulatory Effects of Curcumin on the Tumor Microenvironment in Head and Neck Squamous Cell Carcinoma

Simple Summary

Head and neck squamous cell carcinoma has been shown to downregulate the host’s antitumor immune response as well as inherent anticancer immunity, inter alia, via increased activation of nuclear factor kappa of activated B-cells (NF-κB). The aim of this study is to examine curcumin’s effects on certain pro- and antitumoral chemokines via NF-κB, as well as the combined effects of curcumin and toll-like receptor 3 agonist Poly I:C on NF-κB and regulatory T-cell attraction. Furthermore, we compare curcumin with established NF-κB inhibitors caffeic acid phenethyl ester and BAY 11-7082. We demonstrate that curcumin has immune-modulating effects, with potent inhibition of the regulatory T-cell-attracting effects of Poly I:C. Therefore, curcumin presents an adjuvant that not only improves the effects of established therapies but also holds the potential to reduce negative side effects in tumor entities with increased NF-κB activation.

Abstract

Curcumin is known to have immune-modulatory and antitumor effects by interacting with more than 30 different proteins. An important feature of curcumin is the inhibition of nuclear factor kappa of activated B-cells (NF-κB). Here, we evaluate the potential of curcumin to reverse the epithelial to mesenchymal transition (EMT) of head and neck squamous cell carcinoma (HNSCC) cells as a part of tumor escape mechanisms. We examined the impact of curcumin on the expression of different pro- and antitumoral chemokines in ex vivo HNSCC tumor tissue and primary macrophage cultures. Further, we evaluated the combinatorial effect of curcumin and toll-like receptor 3 (TLR3) agonist Poly I:C (PIC) on NF-κB inhibition and regulatory T-cell (Treg) attraction. Mesenchymal markers were significantly reduced in cancer specimens after incubation with curcumin, with simultaneous reduction of key transcription factors of EMT, Snail, and Twist. Furthermore, a decrease of the Treg-attracting chemokine CCL22 was observed. Additionally, curcumin-related inhibition of NF-κB nuclear translocation was evident. The combination of PIC with curcumin resulted in further NF-κB inhibition, whereas PIC alone contrarily resulted in NF-κB activation. Furthermore, curcumin was more effective in inhibiting PIC-dependent NF-κB activation and Treg attraction compared to known NF-κB inhibitors BAY 11-7082 or caffeic acid phenethyl ester (CAPE). The presented results show, for the first time, the immune-modulating effects of curcumin in HNSCC, with potent inhibition of the Treg-attracting effects of PIC. Hence, curcumin presents a promising drug in cancer therapy as a supplement to already established treatments.

Effect of disease duration in a randomized Phase III trial of rintatolimod, an immune modulator for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

BACKGROUND

Rintatolimod is a selective TLR3 agonist, which has demonstrated clinical activity for ME/CFS in Phase II and Phase III double-blind, placebo-controlled, randomized, multi-site clinical trials.

METHODS AND FINDINGS

A hypothesis-based post-hoc analysis of the Intent to Treat (ITT) population diagnosed with ME/CFS from 12 independent clinical sites of a Phase III trial was performed to evaluate the effect of rintatolimod therapy based on disease duration. The clinical activity of rintatolimod was evaluated by exercise treadmill tolerance (ETT) using a modified Bruce protocol. The ITT population (n = 208) was divided into two subsets of symptom duration. Patients with symptom duration of 2-8 years were identified as the Target Subset (n = 75); the remainder (<2 year plus >8 year) were identified as the Non-Target Subset (n = 133). Placebo-adjusted percentage improvements in exercise duration and the vertical rise for the Target Subset (n = 75) were more than twice that of the ITT population. The Non-Target Subset (n = 133) failed to show any clinically significant ETT response to rintatolimod when compared to placebo. Within the Target Subset, 51.2% of rintatolimod-treated patients improved their exercise duration by ≥25% (p = 0.003) despite reduced statistical power from division of the original ITT population into two subsets.

CONCLUSION/SIGNIFICANCE

Analysis of ETT from a Phase III trial has identified within the ITT population, a subset of ME/CFS patients with ≥2 fold increased exercise response to rintatolimod. Substantial improvement in physical performance was seen for the majority (51.2%) of these severely debilitated patients who improved exercise duration by ≥25%. This magnitude of exercise improvement was associated with clinically significant enhancements in quality of life. The data indicate that ME/CFS patients have a relatively short disease duration window (<8 years) to expect a significant response to rintatolimod under the dosing conditions utilized in this Phase III clinical trial. These results may have direct relevance to the cognitive impairment and fatigue being experienced by patients clinically recovered from COVID-19 and free of detectable SARS-CoV-2.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT00215800.

From animal models to patients: the role of placental microRNAs, miR-210, miR-126, and miR-148a/152 in preeclampsia

Placental microRNAs (miRNAs) regulate the placental transcriptome and play a pathological role in preeclampsia (PE), a hypertensive disorder of pregnancy. Three PE rodent model studies explored the role of placental miRNAs, miR-210, miR-126, and miR-148/152 respectively, by examining expression of the miRNAs, their inducers, and potential gene targets. This review evaluates the role of miR-210, miR-126, and miR-148/152 in PE by comparing findings from the three rodent model studies with in vitro studies, other animal models, and preeclamptic patients to provide comprehensive insight into genetic components and pathological processes in the placenta contributing to PE. The majority of studies demonstrate miR-210 is upregulated in PE in part driven by HIF-1α and NF-κBp50, stimulated by hypoxia and/or immune-mediated processes. Elevated miR-210 may contribute to PE via inhibiting anti-inflammatory Th2-cytokines. Studies report an up- and downregulation of miR-126, arguably reflecting differences in expression between cell types and its multifunctional capacity. MiR-126 may play a pro-angiogenic role by mediating the PI3K-Akt pathway. Most studies report miR-148/152 family members are upregulated in PE. Evidence suggests they may inhibit DNA methylation of genes involved in metabolic and inflammatory pathways. Given the genetic heterogeneity of PE, it is unlikely that a single placental miRNA is a suitable therapeutic target for all patients. Investigating miRNAs in PE subtypes in patients and animal models may represent a more appropriate approach going forward. Developing methods for targeting placental miRNAs and specific placental cell types remains crucial for research seeking to target placental miRNAs as a novel treatment for PE.

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Comprehensive Review

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating chronic disease of unknown aetiology that is recognized by the World Health Organization (WHO) and the United States Center for Disease Control and Prevention (US CDC) as a disorder of the brain. The disease predominantly affects adults, with a peak age of onset of between 20 and 45 years with a female to male ratio of 3:1. Although the clinical features of the disease have been well established within diagnostic criteria, the diagnosis of ME/CFS is still of exclusion, meaning that other medical conditions must be ruled out. The pathophysiological mechanisms are unclear but the neuro-immuno-endocrinological pattern of CFS patients gleaned from various studies indicates that these three pillars may be the key point to understand the complexity of the disease. At the moment, there are no specific pharmacological therapies to treat the disease, but several studies' aims and therapeutic approaches have been described in order to benefit patients' prognosis, symptomatology relief, and the recovery of pre-existing function. This review presents a pathophysiological approach to understanding the essential concepts of ME/CFS, with an emphasis on the population, clinical, and genetic concepts associated with ME/CFS.

Leveraging Prior Knowledge of Endocrine Immune Regulation in the Therapeutically Relevant Phenotyping of Women With Chronic Fatigue Syndrome

PURPOSE

The complex and varied presentation of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) has made it difficult to diagnose, study, and treat. Its symptoms and likely etiology involve multiple components of endocrine and immune regulation, including the hypothalamic-pituitary-adrenal axis, the hypothalamic-pituitary-gonadal axis, and their interactive oversight of immune function. We propose that the persistence of ME/CFS may involve changes in the regulatory interactions across these physiological axes. We also propose that the robustness of this new pathogenic equilibrium may at least in part explain the limited success of conventional single-target therapies.

METHODS

A comprehensive model was constructed of female endocrine-immune signaling consisting of 28 markers linked by 214 documented regulatory interactions. This detailed model was then constrained to adhere to experimental measurements in a subset of 17 candidate immune markers measured in peripheral blood of patients with ME/CFS and healthy control subjects before, during, and after a maximal exercise challenge. A set of 26 competing numerical models satisfied these data to within 5% error.

FINDINGS

Mechanistically informed predictions of endocrine and immune markers that were either unmeasured or exhibited high subject-to-subject variability pointed to possible context-specific overexpression in ME/CFS at rest of corticotropin-releasing hormone, chemokine (C-X-C motif) ligand 8, estrogen, follicle-stimulating hormone (FSH), gonadotropin-releasing hormone 1, interleukin (IL)-23, and luteinizing hormone, and underexpression of adrenocorticotropic hormone, cortisol, interferon-γ, IL-10, IL-17, and IL-1α. Simulations of rintatolimod and rituximab treatment predicted a shift in the repertoire of available endocrine-immune regulatory regimens. Rintatolimod was predicted to make available substantial remission in a significant subset of subjects, in particular those with low levels of IL-1α, IL-17, and cortisol; intermediate levels of progesterone and FSH; and high estrogen levels. Rituximab treatment was predicted to support partial remission in a smaller subset of patients with ME/CFS, specifically those with low norepinephrine, IL-1α, chemokine (C-X-C motif) ligand 8, and cortisol levels; intermediate FSH and gonadotropin-releasing hormone 1 levels; and elevated expression of tumor necrosis factor-α, luteinizing hormone, IL-12, and B-cell activation.

IMPLICATIONS

Applying a rigorous filter of known signaling mechanisms to experimentally measured immune marker expression in ME/CFS has highlighted potential new context-specific markers of illness. These novel endocrine and immune markers may offer useful candidates in delineating new subtypes of ME/CFS and may inform on refinements to the inclusion criteria and instrumentation of new and ongoing trials involving rintatolimod and rituximab treatment protocols.

Helicase-Driven Activation of NFκB-COX2 Pathway Mediates the Immunosuppressive Component of dsRNA-Driven Inflammation in the Human Tumor Microenvironment

Presence of cytotoxic CD8⁺ T cells (CTL) in tumor microenvironments (TME) is critical for the effectiveness of immune therapies and patients' outcome, whereas regulatory T(reg) cells promote cancer progression. Immune adjuvants, including double-stranded (ds)RNAs, which signal via Toll-like receptor-3 (TLR3) and helicase (RIG-I/MDA5) pathways, all induce intratumoral production of CTL-attractants, but also Treg attractants and suppressive factors, raising the question of whether induction of these opposing groups of immune mediators can be separated. Here, we use human tumor explant cultures and cell culture models to show that the (ds) RNA Sendai Virus (SeV), poly-I:C, and rintatolimod (poly-I:C₁₂U) all activate the TLR3 pathway involving TRAF3 and IRF3, and induce IFNα, ISG-60, and CXCL10 to promote CTL chemotaxis to ex vivo-treated tumors. However, in contrast with SeV and poly I:C, rintatolimod did not activate the MAVS/helicase pathway, thus avoiding NFκB- and TNFα-dependent induction of COX2, COX2/PGE2-dependent induction of IDO, IL10, CCL22, and CXCL12, and eliminating Treg attraction. Induction of CTL-attractants by either poly I:C or rintatolimod was further enhanced by exogenous IFNα (enhancer of TLR3 expression), whereas COX2 inhibition enhanced the response to poly-I:C only. Our data identify the helicase/NFκB/TNFα/COX2 axis as the key suppressive pathway of dsRNA signaling in human TME and suggest that selective targeting of TLR3 or elimination of NFκB/TNFα/COX2-driven suppression may allow for selective enhancement of type-1 immunity.Significance: This study characterizes two different poly-I:C-induced signaling pathways in their induction of immunostimulatory and suppressive factors and suggests improved ways to reprogram the TME to enhance the antitumor efficacy of immunotherapies. Cancer Res; 78(15); 4292-302. ©2018 AACR.

Efficacy of rintatolimod in the treatment of chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME)

Chronic fatigue syndrome/ Myalgic encephalomyelitis (CFS/ME) is a poorly understood seriously debilitating disorder in which disabling fatigue is an universal symptom in combination with a variety of variable symptoms. The only drug in advanced clinical development is rintatolimod, a mismatched double stranded polymer of RNA (dsRNA). Rintatolimod is a restricted Toll-Like Receptor 3 (TLR3) agonist lacking activation of other primary cellular inducers of innate immunity (e.g.- cytosolic helicases). Rintatolimod also activates interferon induced proteins that require dsRNA for activity (e.g.- 2ʹ-5ʹ adenylate synthetase, protein kinase R). Rintatolimod has achieved statistically significant improvements in primary endpoints in Phase II and Phase III double-blind, randomized, placebo-controlled clinical trials with a generally well tolerated safety profile and supported by open-label trials in the United States and Europe. The chemistry, mechanism of action, clinical trial data, and current regulatory status of rintatolimod for CFS/ME including current evidence for etiology of the syndrome are reviewed.

Triggering Intracellular Receptors for Vaccine Adjuvantation

Immune adjuvants are components that stimulate, potentiate, or modulate the immune response to an antigen. They are key elements of vaccines in both the prophylactic and therapeutic domains. In the past decade substantial progress in our understanding of innate immunity has paved the way for the design of next-generation adjuvants that stimulate a wide range of receptors. Within the framework of vaccine adjuvant design, this review outlines the interest of targeting endosomal and intracellular receptors to enhance and guide the immune response. We present and compare the molecules as well as potential combinations which are currently in the spotlight. We emphasize how targeting the appropriate receptor can direct immunity towards the appropriate response, such as a cytotoxic or mucosal response.

TLR3 Agonist Poly-IC Induces IL-33 and Promotes Myelin Repair

Background

Impaired remyelination of demyelinated axons is a major cause of neurological disability. In inflammatory demyelinating disease of the central nervous system (CNS), although remyelination does happen, it is often incomplete, resulting in poor clinical recovery. Poly-IC a known TLR3 agonist and IL-33, a cytokine which is induced by poly-IC are known to influence recovery and promote repair in experimental models of CNS demyelination.

Methodology and Principal Findings

We examined the effect of addition of poly-IC and IL-33 on the differentiation and maturation of oligodendrocyte precursor cells (OPC) cultured in vitro. Both Poly-IC and IL-33 induced transcription of myelin genes and the differentiation of OPC to mature myelin forming cells. Poly-IC induced IL-33 in OPC and addition of IL-33 to in vitro cultures, amplified further, IL-33 expression suggesting an autocrine regulation of IL-33. Poly-IC and IL-33 also induced phosphorylation of p38MAPK, a signaling molecule involved in myelination. Following the induction of gliotoxic injury with lysolecithin to the corpus callosum (CC), treatment of animals with poly-IC resulted in greater recruitment of OPC and increased staining for myelin in areas of demyelination. Also, poly-IC treated animals showed greater expression of IL-33 and higher expression of M2 phenotype macrophages in the CC.

Conclusion/Significance

Our studies suggest that poly-IC and IL-33 play a role in myelin repair by enhancing expression of myelin genes and are therefore attractive therapeutic agents for use as remyelinating agents in human demyelinating disease.