toll-like receptors – American ME and CFS Society

Novel TLR7 hemizygous variant in post-COVID-19 neurological deterioration: a case report with literature review

Abstract:

The neurological complications of coronavirus disease 2019 (COVID-19) can range from simple tremors and dystonia to features of encephalopathy. Toll-like receptor 7 (TLR7) belongs to a family of innate immune receptors responsible for viral RNA detection (such as SARS-CoV-2) and immune response initiation. TLR7 loss of function variants have been previously reported as genetic risk factors for severe COVID-19 infection in young patients with no comorbidities.

In this case, we report a pediatric patient who developed severe long-term neurological deterioration following his COVID-19 infection. Presenting first to the clinic with episodic dystonia and finger spasticity, the patient’s condition rapidly deteriorated with a significant drop in the Glasgow Coma Scale (GCS). Despite improvement following initial treatment with rituximab and intravenous immunoglobulin, the patient’s symptoms relapsed, and GCS further dropped to 3/15.

Serial brain magnetic resonance imaging scans revealed diffuse parenchymal atrophy, ventricular enlargement, and spinal cord thickening. Autoimmune investigations were negative but clinical whole genome sequencing prioritized four gene variants, the most significant of which was a novel frameshift null variant of the X chromosomal TLR7 gene (c.1386_1389dup, p.[His464Ilefs*7]). This case illustrates a role for TLR7 in long-term COVID-19 complications and highlights that TLR7 deficiency in the future may be addressed as a therapeutic measure.

Source: Noor Eddin A, Al-Rimawi M, Peer-Zada F, Hundallah K, Alhashem A. Novel TLR7 hemizygous variant in post-COVID-19 neurological deterioration: a case report with literature review. Front Neurol. 2023 Nov 29;14:1268035. doi: 10.3389/fneur.2023.1268035. PMID: 38093758; PMCID: PMC10716429. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10716429/ (Full text)

Compounding for the Treatment of COVID-19 and Long COVID, Part 3: The Role of Toll-like Receptors in SARS-CoV-2 Infection and COVID Development

Abstract:

Toll-like receptors, which are type I transmembrane proteins and pattern recognition receptors found on cell surfaces and in intracellular membranes, serve as central mediators of both initial innate-immune responses and secondary adaptive/acquired-immune responses. Toll-like receptor 4, the activation of which leads to the synthesis of proinflammatory cytokines and chemokines, has been shown to have a vital role in the innate immune response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. In our practice of pharmaceutical compounding, we noted that some individuals with coronavirus disease- 2019 (COVID-19) or long COVID achieved limited or no benefit from commercially manufactured treatments designed to alleviate symptoms and enable recovery. We suggest that in such cases, a compounded formulation, which can be easily customized to provide that support, may be of benefit.

This article provides a brief review of the ways in which toll-like receptors in general, and toll-like receptor 4 in particular, affect the development and progression of SARS-CoV-2 infection and COVID-19, especially with respect to the human respiratory and central nervous systems and people rendered vulnerable by a comorbid condition (diabetes, obesity) or age. Instructions for compounding 2 customized preparations useful in the treatment of COVID-19 and long COVID are also provided.

Source: Riepl M, Kaiser J. Compounding for the Treatment of COVID-19 and Long COVID, Part 3: The Role of Toll-like Receptors in SARS-CoV-2 Infection and COVID Development. Int J Pharm Compd. 2023 May-Jun;27(3):192-200. PMID: 37267521.

Partners in crime: Autoantibodies complicit in COVID-19 pathogenesis

Abstract:

Autoantibodies (AABs) play a critical role in the pathogenesis of autoimmune diseases (AIDs) and serve as a diagnostic and prognostic tool in assessing these complex disorders. Viral infections have long been recognized as a principal environmental factor affecting the production of AABs and the development of autoimmunity. COVID-19 has primarily been considered a hyperinflammatory syndrome triggered by a cytokine storm. In the following, the role of maladaptive B cell response and AABs became more apparent in COVID-19 pathogenesis.

The current review will primarily focus on the role of extrafollicular B cell response, Toll-like receptor-7 (TLR-7) activation, and neutrophil extracellular traps (NETs) formation in the development of AABs following SARS-CoV-2 infection. In the following, this review will clarify how these AABs dysregulate immune response to SARS-CoV-2 by disrupting cytokine function and triggering neutrophil hyper-reactivity.

Finally, the pathologic effects of these AABs will be further described in COVID-19 associate clinical manifestations, including venous and arterial thrombosis, a multisystem inflammatory syndrome in children (MIS-C), acute respiratory distress syndrome (ARDS), and recently described post-acute sequelae of COVID-19 (PASC) or long-COVID.

Source: Taghadosi M, Safarzadeh E, Asgarzadeh A, Roghani SA, Shamsi A, Jalili C, Assar S, Soufivand P, Pournazari M, Feizollahi P, Nicknam MH, Asghariazar V, Vaziri S, Shahriari H, Mohammadi A. Partners in crime: Autoantibodies complicit in COVID-19 pathogenesis. Rev Med Virol. 2022 Dec 5:e2412. doi: 10.1002/rmv.2412. Epub ahead of print. PMID: 36471421. https://pubmed.ncbi.nlm.nih.gov/36471421/ https://www.researchgate.net/publication/366031618_Partners_in_crime_Autoantibodies_complicit_in_COVID-19_pathogenesis (Full text)

Genetics of COVID-19 and myalgic encephalomyelitis/chronic fatigue syndrome: a systematic review

Abstract:

COVID-19 and ME/CFS present with some similar symptoms, especially physical and mental fatigue. In order to understand the basis of these similarities and the possibility of underlying common genetic components, we performed a systematic review of all published genetic association and cohort studies regarding COVID-19 and ME/CFS and extracted the genes along with the genetic variants investigated. We then performed gene ontology and pathway analysis of those genes that gave significant results in the individual studies to yield functional annotations of the studied genes using protein analysis through evolutionary relationships (PANTHER) VERSION 17.0 software. Finally, we identified the common genetic components of these two conditions.

Seventy-one studies for COVID-19 and 26 studies for ME/CFS were included in the systematic review in which the expression of 97 genes for COVID-19 and 429 genes for ME/CFS were significantly affected. We found that ACE, HLA-A, HLA-C, HLA-DQA1, HLA-DRB1, and TYK2 are the common genes that gave significant results. The findings of the pathway analysis highlight the contribution of inflammation mediated by chemokine and cytokine signaling pathways, and the T cell activation and Toll receptor signaling pathways. Protein class analysis revealed the contribution of defense/immunity proteins, as well as protein-modifying enzymes. Our results suggest that the pathogenesis of both syndromes could involve some immune dysfunction.

Source: Tziastoudi M, Cholevas C, Stefanidis I, Theoharides TC. Genetics of COVID-19 and myalgic encephalomyelitis/chronic fatigue syndrome: a systematic review. Ann Clin Transl Neurol. 2022 Oct 6. doi: 10.1002/acn3.51631. Epub ahead of print. PMID: 36204816. https://onlinelibrary.wiley.com/doi/10.1002/acn3.51631 (Full text)

Sciatic-Vagal Nerve Stimulation by Electroacupuncture Alleviates Inflammatory Arthritis in Lyme Disease-Susceptible C3H Mice

Abstract:

Lyme disease is caused by Borrelia burgdorferi, and the pathogenesis of the disease is complex with both bacterial and host factors contributing to inflammatory responses. Lyme disease affects different organs including joints and results in arthritis. Immune responses stimulated by B. burgdorferi through toll-like receptors cause infiltration of leukocytes, which produce inflammatory cytokines and facilitate spirochete clearance.

However, arthritic manifestations and chronic fatigue syndrome-like symptoms persist long after completion of antibiotic treatment regimens in a significant number of patients. To counter the effects of inflammation, treatment by non-steroidal anti-inflammatory drugs, hydroxychloroquine, or synovectomy to eradicate inflammatory arthritis in the involved joint could be employed; however, they often have long-term consequences.

Acupuncture has been used for a long time in Asian medicine to diminish pain during various ailments, but the effects and its mechanism are just beginning to be explored. Control of inflammation by neuronal stimulation has been exploited as a systemic therapeutic intervention to arrest inflammatory processes.

Our objective was to determine whether activation of the sciatic-vagal network by electroacupuncture on ST36 acupoint, which is used to control systemic inflammation in experimental models of infectious disorders such as endotoxemia, can also alleviate Lyme arthritis symptoms in mice. This aim was further strengthened by the reports that sciatic-vagal neuronal network stimulation can lead to dopamine production in the adrenal medulla and moderate the production of inflammatory factors.

We first assessed whether electroacupuncture affects spirochete colonization to attenuate Lyme arthritis. Interestingly, bioluminescent B. burgdorferi burden detected by live imaging and qPCR were similar in electroacupuncture- and mock-treated mice, while electroacupuncture induced a lasting anti-inflammatory effect on mice. Despite the discontinuation of treatment at 2 weeks, the simultaneous decrease in neutrophils in the joints and inflammatory cytokine levels throughout the body at 4 weeks suggests a systemic and persistent effect of electroacupuncture that attenuates Lyme arthritis.

Our results suggest that electroacupuncture-mediated anti-inflammatory responses could offer promising healthcare benefits in patients suffering from long-term Lyme disease manifestations.

Source: Akoolo L, Djokic V, Rocha SC, Ulloa L, Parveen N. Sciatic-Vagal Nerve Stimulation by Electroacupuncture Alleviates Inflammatory Arthritis in Lyme Disease-Susceptible C3H Mice. Front Immunol. 2022 Jul 18;13:930287. doi: 10.3389/fimmu.2022.930287. PMID: 35924250; PMCID: PMC9342905. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9342905/ (Full text)

Epstein-Barr Virus dUTPase Induces Neuroinflammatory Mediators: Implications for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome

Abstract:

PURPOSE: Neuroinflammation is a common feature in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), affecting 85%-90% of all patients, yet the underlying mechanism or mechanisms responsible for the initiation and/or promotion of this process is largely unknown. Multiple reports, however, have suggested a role for Epstein-Barr virus (EBV), in particular, in ME/CFS, but its potential role, if any, in the neuroinflammatory process has not been addressed. In support of this premise, studies by our group have found that the EBV protein deoxyuridine triphosphate nucleotidohydrolase (dUTPase) induces anxiety and sickness behaviors in female mice. We also found that a small subset of patients with ME/CFS exhibited prolonged and significantly elevated neutralizing antibodies against EBV dUTPase protein in serum, which inversely correlated with ME/CFS symptoms. A larger ME/CFS case-control cohort study further confirmed that a significant percentage of patients with ME/CFS (30.91%-52.7%) were simultaneously producing antibodies against multiple human herpesviruses-encoded dUTPases and/or human dUTPase. Altogether, these findings suggest that EBV dUTPase protein may be involved in the neuroinflammatory process observed in ME/CFS. Thus, the aim of the present study was to determine whether the EBV dUTPase protein could contribute to neuroinflammation by altering the expression of genes involved with maintaining blood-brain barrier (BBB) integrity and/or modulating synaptic plasticity.

METHODS: With the use of human immortalized astrocytes, microglia, and cerebral microvascular endothelial cells, we conducted time-course (0-24 h) experiments with EBV dUTPase protein (10 μg/mL) to determine what effect(s) it may have on the expression of genes involved with BBB permeability, astrocytes and microglia cell function, tryptophan metabolism, and synaptic plasticity by quantitative reverse transcription polymerase chain reaction (qRT-PCR). In parallel, in vivo studies were conducted in female C57Bl/6 mice. Mice were injected by the intraperitoneal route with EBV dUTPase protein (10 μg) or vehicle daily for 5 days, and the brains were collected and processed for further qRT-PCR analysis of the in vivo effect of the dUTPase on the dopamine/serotonin and γ-aminobutyric acid/glutamate pathways, which are important for brain function, using RT2 Profiler PCR Arrays.

FINDINGS: EBV dUTPase protein altered the expression in vitro (12 of 15 genes and 32 of 1000 proteins examined) and in vivo (34 of 84 genes examined) of targets with central roles in BBB integrity/function, fatigue, pain synapse structure, and function, as well as tryptophan, dopamine, and serotonin metabolism.

IMPLICATIONS: The data suggest that in a subset of patients with ME/CFS, the EBV dUTPase could initiate a neuroinflammatory reaction, which contributes to the fatigue, excessive pain, and cognitive impairments observed in these patients.

Glial Activation and Expression of the Serotonin Transporter in Chronic Fatigue Syndrome

Fatigue is commonly reported in a variety of illnesses and has major impact on quality of life. Chronic fatigue syndrome (CFS) is a debilitating syndrome of unknown etiology. The clinical symptoms include problems in neuroendocrine, autonomic, and immune systems. It is becoming clear that the brain is the central regulator of CFS. For example, neuroinflammation, especially induced by activation of microglia and astrocytes, may play a prominent role in the development of CFS, though little is known about molecular mechanisms.

Many possible causes of CFS have been proposed. However, in this mini-review, we summarize evidence for a role for microglia and astrocytes in the onset and the maintenance of immunologically induced CFS. In a model using virus mimicking synthetic double-stranded RNA, infection causes sequential signaling such as increased blood brain barrier (BBB) permeability, microglia/macrophage activation through Toll-like receptor 3 (TLR3) signaling, secretion of IL-1β, upregulation of the serotonin transporter (5-HTT) in astrocytes, reducing extracellular serotonin (5-HT) levels and hence reduced activation of 5-HT1A receptor subtype. Hopefully, drug discovery targeting these pathways may be effective for CFS therapy.

Source: Mami Noda, Masataka Ifuku, Md. Shamim Hossain and Toshihiko Katafuchi. Glial Activation and Expression of the Serotonin Transporter in Chronic Fatigue Syndrome. Front. Psychiatry, 16 November 2018 | https://doi.org/10.3389/fpsyt.2018.00589 https://www.frontiersin.org/articles/10.3389/fpsyt.2018.00589/full (Full article)

Investigation of mast cell toll-like receptor 3 in Chronic Fatigue Syndrome/Myalgic Encephalomyelitis and Systemic Mastocytosis participants using the novel application of autoMACS magnetic separation and flow cytometry

Abstract:

BACKGROUND: Viral infections and hypersensitivities are commonly reported by Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME) patients. Mast Cells (MC) uniquely mediate type 1 hypersensitivities and resolve viral infections via toll-like receptor 3 (TLR3).

OBJECTIVE: To characterise and compare mast cell progenitors (MCPs) in CFS/ME participants with a known MC disorder, Systemic mastocytosis (SM), and secondly, to investigate the role of MC TLR3 in CFS/ME participants following Polyinosinic:polycytidylic acid (Poly I:C) stimulation.

METHODS: A total of 11 International Consensus Criteria defined CFS/ME participants (40.42 ± 10.31), 9 World Health Organisation defined systemic mastocytosis (SM) participants (47.00 ± 10.37) and 12 healthy controls (HC) (36.36 ± 9.88) were included. Following autoMACS magnetic separation, CD117+/Lin-MCPs were stimulated with Poly I:C for 24hr. MCP purity (CD117 and Lin2), maturity (CD34 and FcεRI), interaction receptors and ligands (CD154 and HLA-DR), and SM-specific (CD2 and CD25) markers were measured using flow cytometry.

RESULTS: There was a significant decrease in HLA-DR+/CD154- expression between CFS/ME and SM groups pre and post Poly I:C stimulation. There were no significant differences in maturity MCPs, CD154, and CD2/CD25 expression between groups pre and post Poly I:C stimulation.

CONCLUSION: This pilot investigation provides a novel methodology to characterise MCPs in a rapid, inexpensive and less invasive fashion. We report a significant decrease in HLA-DR+/CD154- expression between CFS/ME and SM participants, and an observed increase in HLA-DR-/CD154+ expression post Poly I:C stimulation in CFS/ME participants. Peripheral MCPs may be present in CFS/ME pathophysiology, however further investigation is required to determine their immunological role.

Source: Balinas C, Nguyen T, Johnston S, Smith P, Staines D, Marshall-Gradisnik S. Investigation of mast cell toll-like receptor 3 in Chronic Fatigue Syndrome/Myalgic Encephalomyelitis and Systemic Mastocytosis participants using the novel application of autoMACS magnetic separation and flow cytometry. Asian Pac J Allergy Immunol. 2017 Dec 10. doi: 10.12932/AP-200517-0086. [Epub ahead of print] https://www.ncbi.nlm.nih.gov/pubmed/29223146

Central pathways causing fatigue in neuro-inflammatory and autoimmune illnesses

Abstract:

BACKGROUND: The genesis of severe fatigue and disability in people following acute pathogen invasion involves the activation of Toll-like receptors followed by the upregulation of proinflammatory cytokines and the activation of microglia and astrocytes. Many patients suffering from neuroinflammatory and autoimmune diseases, such as multiple sclerosis, Parkinson’s disease and systemic lupus erythematosus, also commonly suffer from severe disabling fatigue.

Such patients also present with chronic peripheral immune activation and systemic inflammation in the guise of elevated proinflammtory cytokines, oxidative stress and activated Toll-like receptors. This is also true of many patients presenting with severe, apparently idiopathic, fatigue accompanied by profound levels of physical and cognitive disability often afforded the non-specific diagnosis of chronic fatigue syndrome.

DISCUSSION: Multiple lines of evidence demonstrate a positive association between the degree of peripheral immune activation, inflammation and oxidative stress, gray matter atrophy, glucose hypometabolism and cerebral hypoperfusion in illness, such as multiple sclerosis, Parkinson’s disease and chronic fatigue syndrome. Most, if not all, of these abnormalities can be explained by a reduction in the numbers and function of astrocytes secondary to peripheral immune activation and inflammation.

This is also true of the widespread mitochondrial dysfunction seen in otherwise normal tissue in neuroinflammatory, neurodegenerative and autoimmune diseases and in many patients with disabling, apparently idiopathic, fatigue. Given the strong association between peripheral immune activation and neuroinflammation with the genesis of fatigue the latter group of patients should be examined using FLAIR magnetic resonance imaging (MRI) and tested for the presence of peripheral immune activation.

SUMMARY: It is concluded that peripheral inflammation and immune activation, together with the subsequent activation of glial cells and mitochondrial damage, likely account for the severe levels of intractable fatigue and disability seen in many patients with neuroimmune and autoimmune diseases.This would also appear to be the case for many patients afforded a diagnosis of Chronic Fatigue Syndrome.

Source: Morris G, Berk M, Walder K, Maes M. Central pathways causing fatigue in neuro-inflammatory and autoimmune illnesses. BMC Med. 2015 Feb 6;13:28. doi: 10.1186/s12916-014-0259-2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4320458/ (Full article)

The Role of Toll-Like Receptors in Chronic Fatigue Syndrome/Myalgic Encephalomyelitis: A New Promising Therapeutic Approach?

Abstract:

Perturbations in immune processes play an important role in chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME), a multifactorial disorder mainly characterized by severe and prolonged fatigue and typically affecting a variety of bodily systems including the immune system.

Recent reports have shown that CFS/ME is an inflammatory disorder may be associated with autoimmune responses, mainly characterized by reduced functional activity of most immune cells, including neutrophils, natural killer cells, monocytes/macrophage and dendritic cells, together with dysregulations in cytokine levels, responsible for changes in the adaptive immune system.

Interactions between gut microorganisms and host immune function have been shown to contribute to aberrant inflammation in CFS/ME patients. Commensal and/or pathogen-associated molecular patterns detected by Toll-like receptors (TLRs) expressed on intestinal epithelial cells appear to trigger inflammatory signaling cascade leading to neuroinflammation and neurodegeneration. This paper examines the role of TLR-mediated innate immunity in CFS/ME with evaluation of the current literature, also discussing about innovative therapeutic approaches represented by immunomodulators TLR-targeting.

Source: Gambuzza ME, Salmeri FM, Soraci L, Soraci G, Sofo V, Marino S, Bramanti P. The Role of Toll-Like Receptors in Chronic Fatigue Syndrome/Myalgic Encephalomyelitis: A New Promising Therapeutic Approach? CNS Neurol Disord Drug Targets. 2015;14(7):903-14. https://www.ncbi.nlm.nih.gov/pubmed/25808894