The role of type I IFN in autoimmune and autoinflammatory diseases with CNS involvement

Varicella-zoster virus-related neurological complications: From infection to immunomodulatory therapies

The Varicella-zoster virus (VZV), classified as a neurotropic member of the Herpesviridae family, exhibits a characteristic pathogenicity, predominantly inducing varicella, commonly known as chickenpox, during the initial infectious phase, and triggering the reactivation of herpes zoster, more commonly recognized as shingles, following its emergence from a latent state. The pathogenesis of VZV-associated neuroinflammation involves a complex interplay between viral replication within sensory ganglia and immune-mediated responses that contribute to tissue damage and dysfunction. Upon primary infection, VZV gains access to sensory ganglia, establishing latent infection within neurons. During reactivation, the virus can spread along sensory nerves, triggering a cascade of inflammatory mediators, chemokines, and immune cell infiltration in the affected neural tissues. The role of both adaptive and innate immune reactions, including the contributions of T and B cells, macrophages, and dendritic cells, in orchestrating the immune-mediated damage in the central nervous system is elucidated. Furthermore, the aberrant activation of the natural defence mechanism, characterised by the dysregulated production of immunomodulatory proteins and chemokines, has been implicated in the pathogenesis of VZV-induced neurological disorders, such as encephalitis, myelitis, and vasculopathy. The intricate balance between protective and detrimental immune responses in the context of VZV infection emphasises the necessity for an exhaustive comprehension of the immunopathogenic mechanisms propelling neuroinflammatory processes. Despite the availability of vaccines and antiviral therapies, VZV-related neurological complications remain a significant concern, particularly in immunocompromised individuals and the elderly. Elucidating these mechanisms might facilitate the emergence of innovative immunomodulatory strategies and targeted therapies aimed at mitigating VZV-induced neuroinflammatory damage and improving clinical outcomes. This comprehensive understanding enhances our grasp of viral pathogenesis and holds promise for pioneering therapeutic strategies designed to mitigate the neurological ramifications of VZV infections.

Type I interferon regulates interleukin-1beta and IL-18 production and secretion in human macrophages

Inflammasomes are immune complexes whose activation leads to the release of pro-inflammatory cytokines IL-18 and IL-1β. Type I IFNs play a role in fighting infection and stimulate the expression of IFN-stimulated genes (ISGs) involved in inflammation. Despite the importance of these cytokines in inflammation, the regulation of inflammasomes by type I IFNs remains poorly understood. Here, we analysed RNA-sequencing data from patients with monogenic interferonopathies and found an up-regulation of several inflammasome-related genes. To investigate the effect of type I IFN on the inflammasome, we treated human monocyte-derived macrophages with IFN-α and observed an increase in CASP1 and GSDMD mRNA levels over time, whereas IL1B and NLRP3 were not directly correlated to IFN-α exposure time. IFN-α treatment reduced the release of mature IL-1β and IL-18, but not caspase-1, in response to ATP-mediated NLRP3 inflammasome activation, suggesting regulation occurs at cytokine expression levels and not the inflammasome itself. However, more studies are required to investigate how regulation by IFN-α occurs and impacts NLRP3 and other inflammasomes at both transcriptional and post-translational levels.

The fluctuations of expression profiles of critical genes in the miRNA maturation process and pro-and anti-inflammatory cytokines in the pathogenesis and progression of multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) is a central nervous system disease known for immune-mediated demyelination, inflammatory, and neurodegeneration symptoms. Discovering molecular biomarkers to classify RRMS and SPMS patients, monitor the disease activity, and response to particular treatments is one area that has received notable attraction. MicroRNA (miRNA), a single-stranded non-coding RNA molecule, is a significant regulator of gene expression recruited in pathogenic mechanisms in diverse diseases, especially cancer and MS. Also, the relapsing-remitting features of MS exhibit that both inflammatory and anti-inflammatory cytokines are effective in the progression of the disease over time.

METHODS AND RESULTS

It was assessed the expression patterns of the genes (Drosha, Pasha (DGCR8), and Dicer ) encoding the critical enzymes in the processing steps of miRNA maturation and major pro-inflammatory and anti-inflammatory cytokines (IFN-α, IFN-β, and IL-6) in blood cells of 40 MS patients (two groups of 10 men and women in both clinical courses of RR and SPMS patients) in comparison with 20 healthy control group (10 males and 10 females). The highest transcription activity of Drosha was observed for RRMS patients (4.2 and 3.6-fold, respectively), and the expression ratio was down regulated in male and female patients with SPMS (3.9- and 3.1-fold, respectively). Considering the studied cytokines, the increase in expression ratio of IL-6 in SPMS patients and the decrease in transcript abundance of INF-α, and INF-β cytokines are consistent with the progression of the disease.

CONCLUSIONS

Our findings showed that the high and low transcriptional levels of the considered genes seem to be effective in the pathogenesis and progression of MS.

Aicardi-Goutières syndrome: A monogenic type I interferonopathy

Aicardi-Goutières syndrome (AGS) is a rare monogenic autoimmune disease that primarily affects the brains of children patients. Its main clinical features include encephalatrophy, basal ganglia calcification, leukoencephalopathy, lymphocytosis and increased interferon-α (IFN-α) levels in the patient's cerebrospinal fluid (CSF) and serum. AGS may be caused by mutations in any one of nine genes (TREX1, RNASEH2A, RNASEH2B, RNASEH2C, SAMHD1, ADAR1, IFIH1, LSM11 and RNU7-1) that result in accumulation of self-nucleic acids in the cytoplasm or aberrant sensing of self-nucleic acids. This triggers overproduction of type I interferons (IFNs) and subsequently causes AGS, the prototype of type I interferonopathies. This review describes the discovery history of AGS with various genotypes and provides the latest knowledge of clinical manifestations and causative genes of AGS. The relationship between AGS and type I interferonopathy and potential therapeutic methods for AGS are also discussed in this review.

Endothelial type I interferon response and brain diseases: identifying STING as a therapeutic target

The endothelium layer lining the inner surface of blood vessels serves relevant physiological functions in all body systems, including the exchanges between blood and extravascular space. However, endothelial cells also participate in innate and adaptive immune response that contribute to the pathophysiology of inflammatory disorders. Type I Interferon (IFN) signaling is an inflammatory response triggered by a variety of pathogens, but it can also be induced by misplaced DNA in the cytosol caused by cell stress or gene mutations. Type I IFN produced by blood leukocytes or by the endothelium itself is well-known to activate the interferon receptor (IFNAR) in endothelial cells. Here, we discuss the induction of type I IFN secretion and signaling in the endothelium, specifically in the brain microvasculature where endothelial cells participate in the tight blood-brain barrier (BBB). This barrier is targeted during neuroinflammatory disorders such as infection, multiple sclerosis, Alzheimer's disease and traumatic brain injury. We focus on type I IFN induction through the cGAS-STING activation pathway in endothelial cells in context of autoinflammatory type I interferonopathies, inflammation and infection. By comparing the pathophysiology of two separate infectious diseases-cerebral malaria induced by Plasmodium infection and COVID-19 caused by SARS-CoV-2 infection-we emphasize the relevance of type I IFN and STING-induced vasculopathy in organ dysfunction. Investigating the role of endothelial cells as active type I IFN producers and responders in disease pathogenesis could lead to new therapeutic targets. Namely, endothelial dysfunction and brain inflammation may be avoided with strategies that target excessive STING activation in endothelial cells.

Interferon beta-1a sc at 25 years: a mainstay in the treatment of multiple sclerosis over the period of one generation

INTRODUCTION

Interferon beta (IFN beta) preparations are an established group of drugs used for immunomodulation in patients with multiple sclerosis (MS). Subcutaneously (sc) applied interferon beta-1a (IFN beta-1a sc) has been in continuous clinical use for 25 years as a disease-modifying treatment.

AREAS COVERED

Based on data published since 2018, we discuss recent insights from analyses of the pivotal trial PRISMS and its long-term extension as well as from newer randomized studies with IFN beta-1a sc as the reference treatment, the use of IFN beta-1a sc across the patient life span and as a bridging therapy, recent data regarding the mechanisms of action, and potential benefits of IFN beta-1a sc regarding vaccine responses.

EXPERT OPINION

IFN beta-1a sc paved the way to effective immunomodulatory treatment of MS, enabled meaningful insights into the disease process, and remains a valid therapeutic option in selected vulnerable MS patient groups.