Janus kinase inhibition for autoinflammation in patients with DNASE2 deficiency

Unveiling human DNase II: Molecular characterization, gene insights, and functional implications: Human DNase II: Molecular insights & functional implications

This review comprehensively explores the molecular characterization, genetic insights, and functional implications of human DNase II, an enzyme crucial for DNA hydrolysis under acidic conditions. We discuss its purification, identification, and characterization, emphasizing the importance of highly purified samples for accurate analyses as well as for understanding the biochemical properties. The discovery and analysis of DNase II's cDNA and gene have provided crucial insights into its genetic regulation and chromosomal location. Genetic polymorphism in DNase II activity levels, characterized by distinct alleles, provides valuable information on the diversity of enzyme function among individuals. Tissue distribution studies reveal its widespread presence across human tissues, hinting at potential endocrine connections. Clinical implications of DNase II variants, including therapeutic strategies targeting the JAK1 pathway, offering insights into disease mechanisms and potential treatments. Overall, this review serves as a valuable resource for advancing our knowledge of DNase II and its impact on human health and disease.

Dysregulation of the cGAS-STING Pathway in Monogenic Autoinflammation and Lupus

One of the oldest mechanisms of immune defense against pathogens is through detection of foreign DNA. Since human DNA is compartmentalized into the nucleus, its presence in the cytosol heralds a potential threat. The cGAS-STING pathway is one of the most important cytosolic DNA sensing pathways and leads to interferon signaling, inflammasome activation, autophagy, and cell death. While STING signaling is protective at physiologic levels, chronic activation of this pathway can instead drive autoinflammation and autoimmunity. Here we discuss several monogenic disorders of the STING pathway that highlight its impact on both innate and adaptive immunity in the progressive loss of tolerance. The potential relevance of STING signaling in systemic lupus erythematosus is then discussed with a focus on future avenues for monitoring and targeting this pathway.

Regulation and function of the cGAS-MITA/STING axis in health and disease

The innate immune systems detect pathogens via pattern-recognition receptors including nucleic acid sensors and non-nucleic acid sensors. Cyclic guanosine monophosphate-adenosine monophosphate (cGAMP) synthase (cGAS, also known as MB21D1) is a cytosolic DNA sensor that recognizes double-stranded DNA (dsDNA) and catalyzes the synthesis of 2',3'-cGAMP. Subsequently, 2',3'-cGAMP binds to the adaptor protein mediator of IRF3 activation (MITA, also known as STING, MPYS, ERIS, and TMEM173) to activate downstream signaling cascades. The cGAS-MITA/STING signaling critically mediates immune responses against DNA viruses, retroviruses, bacteria, and protozoan parasites. In addition, recent discoveries have extended our understanding of the roles of the cGAS-MITA/STING pathway in autoimmune diseases and cancers. Here, we summarize the identification and activation of cGAS and MITA/STING, present the updated functions and regulatory mechanisms of cGAS-MITA/STING signaling and provide a comprehensive understanding of the cGAS-MITA/STING axis in autoimmune diseases and cancers.

Emerging Place of JAK Inhibitors in the Treatment of Inborn Errors of Immunity

Among inborn errors of immunity (IEIs), some conditions are characterized by inflammation and autoimmunity at the front line and are particularly challenging to treat. Monogenic diseases associated with gain-of-function mutations in genes critical for cytokine signaling through the JAK-STAT pathway belong to this group. These conditions represent good candidates for treatment with JAK inhibitors. Type I interferonopathies, a group of recently identified monogenic auto-inflammatory diseases characterized by excessive secretion of type I IFN, are also good candidates with growing experiences reported in the literature. However, many questions remain regarding the choice of the drug, the dose (in particular in children), the efficacy on the various manifestations, the monitoring of the treatment, and the management of potent side effects in particular in patients with infectious susceptibility. This review will summarize the current experiences reported and will highlight the unmet needs.

Regulation and inhibition of the DNA sensor cGAS

Cell-autonomous sensing of nucleic acids is essential for host defence against invading pathogens by inducing antiviral and inflammatory cytokines. cGAS has emerged in recent years as a non-redundant DNA sensor important for detection of many viruses and bacteria. Upon binding to DNA, cGAS synthesises the cyclic dinucleotide 2'3'-cGAMP that binds to the adaptor protein STING and thereby triggers IRF3- and NFκB-dependent transcription. In addition to infection, the pathophysiology of an ever-increasing number of sterile inflammatory conditions in humans involves the recognition of DNA through cGAS. Consequently, the cGAS/STING signalling axis has emerged as an attractive target for pharmacological modulation. However, the development of cGAS and STING inhibitors has just begun and a need for specific and effective compounds persists. In this review, we focus on cGAS and explore how its activation by immunostimulatory DNA is regulated by cellular mechanisms, viral immune modulators and small molecules. We further use our knowledge of cGAS modulation by cells and viruses to conceptualise potential new ways of pharmacological cGAS targeting.