Anakinra Activates Superoxide Dismutase 2 to Mitigate Inflammasome Activity

NLRP3 and cancer: Pathogenesis and therapeutic opportunities

More than a decade ago IL-1 blockade was suggested as an add-on therapy for the treatment of cancer. This proposal was based on the overall safety record of anti-IL-1 biologics and the anti-tumor properties of IL-1 blockade in animal models of cancer. Today, a new frontier in IL-1 activity regulation has developed with several orally active NLRP3 inhibitors currently in clinical trials, including cancer. Despite an increasing body of evidence suggesting a role of NLRP3 and IL-1-mediated inflammation driving cancer initiation, immunosuppression, growth, and metastasis, NLRP3 activation in cancer remains controversial. In this review, we discuss the recent advances in the understanding of NLRP3 activation in cancer. Further, we discuss the current opportunities for NLRP3 inhibition in cancer intervention with novel small molecules.

Superoxide dismutase 2 as a predictor in patients with hepatitis B virus-associated acute-on-chronic liver failure

The prognosis of hepatitis B virus-associated acute-on-chronic liver failure (HBV-ACLF) is critical in clinical management. We aimed to assess the prognostic efficacy of superoxide dismutase 2 (SOD2) for 90-day mortality in HBV-ACLF patients. The expression patterns of SOD2 in peripheral blood mononuclear cells (PBMCs) were examined in a derivation set (n = 82) by quantitative real-time polymerase chain reaction (RT-qPCR). The results were further validated in a validation set (n = 35). The expression levels of SOD2 were significantly decreased in the derivation set compared to those with chronic hepatitis B (CHB) or the healthy controls (HCs) (P < 0.001). In HBV-ACLF patients, SOD2 levels were negatively correlated with serum total bilirubin (TBIL) (rs = - 0.43, P < 0.001) and model for end-stage liver disease (MELD) scores (rs =  -  0.22, P = 0.047), but positively correlated with alkaline phosphatase (AKP) (rs = 0.23, P = 0.034). SOD2 was identified as an independent risk factor for 90-day mortality in HBV-ACLF patients (hazard ratio: 0.124, 95% confidence interval: 0.059-0.261, P < 0.001). SOD2 yielded a larger area under the receiver operating characteristic curve (AUROC) than the MELD score in predicting 90-day mortality (0.914 vs. 0.712, P < 0.001). Kaplan-Meier analysis revealed a favorable overall survival (OS) for the SOD2 high expression group compared with the SOD2 low expression group in both the derivation and validation sets (P < 0.001). SOD2 has promising potential as a predictor of 90-day mortality in patients with HBV-ACLF.

Pharmacologic Management of Monogenic and Very Early Onset Inflammatory Bowel Diseases

Inflammatory bowel disease (IBD) is treated with a variety of immunomodulating and immunosuppressive therapies; however, for the majority of cases, these therapies are not targeted for specific disease phenotypes. Monogenic IBD with causative genetic defect is the exception and represents a disease cohort where precision therapeutics can be applied. With the advent of rapid genetic sequencing platforms, these monogenic immunodeficiencies that cause inflammatory bowel disease are increasingly being identified. This subpopulation of IBD called very early onset inflammatory bowel disease (VEO-IBD) is defined by an age of onset of less than six years of age. Twenty percent of VEO-IBDs have an identifiable monogenic defect. The culprit genes are often involved in pro-inflammatory immune pathways, which represent potential avenues for targeted pharmacologic treatments. This review will provide an overview of the current state of disease-specific targeted therapies, as well as empiric treatment for undifferentiated causes of VEO-IBD.

Role of mitochondrial stress and the NLRP3 inflammasome in lung diseases

BACKGROUND

As an organelle essential for intracellular energy supply, mitochondria are involved in intracellular metabolism and inflammation, and cell death. The interaction of mitochondria with the NLRP3 inflammasome in the development of lung diseases has been extensively studied. However, the exact mechanism by which mitochondria mediate the activation of the NLRP3 inflammasome and trigger lung disease is still unclear.

METHODS

The literatures related to mitochondrial stress, NLRP3 inflammasome and lung diseases were searched in PubMed.

RESULTS

This review aims to provide new insights into the recently discovered mitochondrial regulation of the NLRP3 inflammasome in lung diseases. It also describes the crucial roles of mitochondrial autophagy, long noncoding RNA, micro RNA, altered mitochondrial membrane potential, cell membrane receptors, and ion channels in mitochondrial stress and regulation of the NLRP3 inflammasome, in addition to the reduction of mitochondrial stress by nuclear factor erythroid 2-related factor 2 (Nrf2). The effective components of potential drugs for the treatment of lung diseases under this mechanism are also summarized.

CONCLUSION

This review provides a resource for the discovery of new therapeutic mechanisms and suggests ideas for the development of new therapeutic drugs, thus promoting the rapid treatment of lung diseases.

NLRP3 inflammasome activation in response to metals

Implant surgery is followed by a series of inflammatory reactions that directly affect its postoperative results. The inflammasome plays a vital role in the inflammatory response by inducing pyroptosis and producing interleukin-1β, which plays a critical role in inflammation and tissue damage. Therefore, it is essential to study the activation of the inflammasome in the bone healing process after implant surgery. As metals are the primary implant materials, metal-induced local inflammatory reactions have received significant attention, and there has been more and more research on the activation of the NLRP3 (NOD-like receptor protein-3) inflammasome caused by these metals. In this review, we consolidate the basic knowledge on the NLRP3 inflammasome structures, the present knowledge on the mechanisms of NLRP3 inflammasome activation, and the studies of metal-induced NLRP3 inflammasome activation.

Role of reactive oxygen species and mitochondrial damage in rheumatoid arthritis and targeted drugs

Rheumatoid arthritis (RA) is an autoimmune disease characterized by synovial inflammation, pannus formation, and bone and cartilage damage. It has a high disability rate. The hypoxic microenvironment of RA joints can cause reactive oxygen species (ROS) accumulation and mitochondrial damage, which not only affect the metabolic processes of immune cells and pathological changes in fibroblastic synovial cells but also upregulate the expression of several inflammatory pathways, ultimately promoting inflammation. Additionally, ROS and mitochondrial damage are involved in angiogenesis and bone destruction, thereby accelerating RA progression. In this review, we highlighted the effects of ROS accumulation and mitochondrial damage on inflammatory response, angiogenesis, bone and cartilage damage in RA. Additionally, we summarized therapies that target ROS or mitochondria to relieve RA symptoms and discuss the gaps in research and existing controversies, hoping to provide new ideas for research in this area and insights for targeted drug development in RA.

Pulmonary drug delivery technology enables anakinra repurposing in cystic fibrosis

Inflammation is a key pathological driver in cystic fibrosis (CF). Current therapies are ineffective in treating and preventing the escalation of inflammatory events often exacerbated by superimposed infection. In this work, we propose a novel treatment based on the pulmonary administration of anakinra, a non-glycosylated recombinant form of IL-1Ra. An inhalable dry powder of anakinra was successfully developed to meet the specific needs of lung drug delivery. The new formulation was investigated in vitro for aerodynamic performances and activity and in vivo for its pharmacological profile, including the pharmacokinetics, treatment schedule, antimicrobial and anti-inflammatory activity and systemic toxicity. The protein was structurally preserved inside the formulation and retained its pharmacological activity in vitro immediately after preparation and over time when stored at ambient conditions. Anakinra when delivered to the lungs showed an improved and extended therapeutic efficacy in CF models in vivo as well as higher potency compared to systemic delivery. Peripheral side effects were significantly reduced and correlated with lower serum levels compared to systemic treatment. These findings provide proof-of-concept demonstration for anakinra repurposing in CF through the pulmonary route.

SS-31 as a Mitochondrial Protectant in the Treatment of Tendinopathy: Evaluation in a Murine Supraspinatus Tendinopathy Model

BACKGROUND

Prior studies have demonstrated mitochondrial dysfunction in tendinopathy. The objective of this investigation was to explore the potential of SS-31 (elamipretide), a mitochondrial protectant, to improve mitochondrial function and promote tendon healing in a murine supraspinatus tendinopathy model.

METHODS

One hundred and twenty-six mice (252 limbs) were divided into 6 groups (42 limbs/group) that received (I) 4 weeks of impingement; (II) 8 weeks of impingement; (III) 8 weeks of impingement including 4 weeks of SS-31 treatment (5 mg/kg/d) starting after 4 weeks of impingement; (IV) 4 weeks of impingement ending with clip removal, followed by harvesting 4 weeks later; and (V) 4 weeks of impingement ending with clip removal, followed by 4 weeks of SS-31 treatment and harvesting; and a control group. Specimens were prepared for biomechanical testing, histological analysis, transmission electron microscopy, measurement of superoxidative dismutase (SOD) activity, and measurement of gene expression.

RESULTS

Failure force decreased after impingement, compared with the intact tendon, and the decrease was partially reversed after clip removal, SS-31 treatment, and the 2 treatments combined. A similar pattern was observed for stiffness. Histological analysis demonstrated higher modified Bonar scores in the impingement groups; however, the changes in tendon morphology were partially reversed following all treatments, especially the combined treatment. Decreased mitochondrial number and altered organization and density of cristae were observed in the impingement groups. Mitochondrial structure and number became more normal, with improvement in morphology of the cristae, after clip removal and/or SS-31 treatment. SOD activity decreased after impingement, compared with the control group, then increased significantly again after treatment, especially in the combined treatment group. Mitochondria-related gene expression decreased in the impingement groups and increased again after treatment.

CONCLUSIONS

The mitochondrial protectant SS-31 improved mitochondrial function, promoting tendon healing, especially when combined with removal of subacromial impingement.

CLINICAL RELEVANCE

Improving mitochondrial function with agents such as SS-31 may represent an effective treatment to promote healing in the setting of supraspinatus tendinopathy.

NLRP3 inflammasome in digestive diseases: From mechanism to therapy

Digestive system diseases remain a formidable challenge to human health. NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome is the most characteristic multimeric protein complex and is involved in a wide range of digestive diseases as intracellular innate immune sensors. It has emerged as a research hotspot in recent years. In this context, we provide a comprehensive review of NLRP3 inflammasome priming and activation in the pathogenesis of digestive diseases, including clinical and preclinical studies. Moreover, the scientific evidence of small-molecule chemical drugs, biologics, and phytochemicals, which acts on different steps of the NLRP3 inflammasome, is reviewed. Above all, deep interrogation of the NLRP3 inflammasome is a better insight of the pathomechanism of digestive diseases. We believe that the NLRP3 inflammasome will hold promise as a novel valuable target and research direction for treating digestive disorders.

Linking Genetic Diagnosis to Therapeutic Approach in Very Early Onset Inflammatory Bowel Disease: Pharmacologic Considerations

Very early onset inflammatory bowel disease (VEO-IBD) is diagnosed in children < 6 years of age, and in rare cases may be due to an identifiable monogenic cause. Recent advances in genetic testing have allowed for more accurate diagnosis, with as many as 100 genes now known to be associated with monogenic inflammatory bowel disease. These genes are involved in many immune pathways and thus may represent potential avenues for targeted precision medicine with pharmacologic treatments aimed at these. This review describes the broad classifications of monogenic disorders known to cause VEO-IBD, as well as empiric and disease-specific medical therapies. These include immune-modulating or immunosuppressant medications, nutritional therapy, surgery, and hematopoietic stem cell transplantation. We aim to provide an overview of the current state of targeted therapy for VEO-IBD.

NLRP3 Inflammasome in Vascular Disease: A Recurrent Villain to Combat Pharmacologically

Despite the great advances in medicine, mortality from cardiovascular diseases keeps on growing. This tendency is not likely to change considering the pandemic proportions of obesity and diabetes. Besides, the global population is more aged as life expectancy increases, and vascular aging plays a key role in the increased risk of vascular disease. In light of recent trials, namely the CANTOS study, showing the enormous potential of anti-inflammatory therapies and in particular those targeted to IL-1β, a change in therapeutical management of cardiovascular diseases is coming about. The NLRP3 inflammasome is a multiprotein complex that assembles to engage the innate immune defense by processing the maturation of pro-inflammatory cytokines IL-1β and IL-18. Substantial evidence has positioned the NLRP3 inflammasome at the center of vascular disease progression, with a particular significance in the context of aging and the low-grade chronic inflammation associated (inflammaging). Therefore, pharmacological blockade of the NLRP3 inflammasome and its end products has arisen as an extremely promising tool to battle vascular disease. In this review, we discuss the mechanisms by which the NLRP3 inflammasome contributes to vascular disease, with particular attention to the consequences of aging, and we enumerate the therapeutic options available to combat this recurrent villain.

Anakinra restores cellular proteostasis by coupling mitochondrial redox balance to autophagy

Autophagy selectively degrades aggregation-prone misfolded proteins caused by defective cellular proteostasis. However, the complexity of autophagy may prevent the full appreciation of how its modulation could be used as a therapeutic strategy in disease management. Here we define a molecular pathway through which recombinant interleukin-1 receptor antagonist (IL-1Ra, anakinra) affects cellular proteostasis independently from the IL-1 receptor (IL-1R1). Anakinra promoted H2O2-driven autophagy through a xenobiotic sensing pathway involving the aryl hydrocarbon receptor that, activated through the indoleamine 2,3-dioxygenase 1-kynurenine pathway, transcriptionally activates NADPH Oxidase 4 independent of the IL-1R1. By coupling the mitochondrial redox balance to autophagy, anakinra improved the dysregulated proteostasis network in murine and human cystic fibrosis. We anticipate that anakinra may represent a therapeutic option in addition to its IL-1R1 dependent anti-inflammatory properties by acting at the intersection of mitochondrial oxidative stress and autophagy with the capacity to restore conditions in which defective proteostasis leads to human disease.

Defective Glyoxalase 1 Contributes to Pathogenic Inflammation in Cystic Fibrosis

Cystic fibrosis (CF) is an autosomal recessive disorder that affects multiple organs, although a decline in respiratory function represents the major cause of morbidity and mortality. The airways of CF patients are characterized by a chronic inflammatory state to which the receptor for advanced glycation end-products greatly contributes. Glyoxalase 1 (GLO1) is the major enzyme metabolizing methylglyoxal, a potent precursor of advanced glycation end-products. Its role in CF has never been investigated. We herein resorted to murine and human preclinical models of CF to define the contribution of GLO1 to inflammatory pathology. We found that the expression and activity of GLO1, measured by real-time PCR and Western blot or a specific spectrophotometric assay, respectively, are defective in mice and human bronchial cells from CF patients exposed to Aspergillus fumigatus, a common pathogen in CF, but could be restored upon blockade of interleukin-1 receptor signaling by anakinra in mice. This study suggests that GLO1 contributes to pathology in CF and may be potentially targeted to mitigate inflammation.