Microcrystalline silica particles induce inflammatory response via pyroptosis in primary human respiratory epithelial cells

Boarding pyroptosis onto nanotechnology for cancer therapy

Pyroptosis, a non-apoptotic programmed cellular inflammatory death mechanism characterized by gasdermin (GSDM) family proteins, has gathered significant attention in the cancer treatment. However, the alarming clinical trial data indicates that pyroptosis-mediated cancer therapeutic efficiency is still unsatisfactory. It is essential to integrate the burgeoning biomedical findings and innovations with potent technology to hasten the development of pyroptosis-based antitumor drugs. Considering the rapid development of pyroptosis-driven cancer nanotherapeutics, here we aim to summarize the recent advances in this field at the intersection of pyroptosis and nanotechnology. First, the foundation of pyroptosis-based nanomedicines (NMs) is outlined to illustrate the reliability and effectiveness for the treatment of tumor. Next, the emerging nanotherapeutics designed to induce pyroptosis are overviewed. Moreover, the cross-talk between pyroptosis and other cell death modalities are discussed, aiming to explore the mechanistic level relationships to provide guidance strategies for the combination of different types of antitumor drugs. Last but not least, the opportunities and challenges of employing pyroptosis-based NMs in potential clinical cancer therapy are highlighted.

Emerging trends in silicosis research: a scientometric review

Silicosis is a global disease whose prevention efforts cannot be ignored today. Although numerous silicosis-related data have been published recently, emphasizing the characteristics and nature of silicosis, a summary of the developmental laws of research is lacking, especially in the visual analysis of the literature. We aim to address this issue through a scientometric review. The Web of Science Core Collection and the All Databases were searched with "silicosis" as the topic, excluding unrelated publications, and obtained data from 9802 and 1613 publications, respectively. The data was then analyzed using the Web of Science's online scientometric analysis function and CiteSpace's visual analysis functionality, including publication volume analysis, co-occurrence analysis, co-citation analysis, cluster analysis, and explosive detection. The results identify the "respiratory system" as the most influential area over a century. Furthermore, the publication's number was correlated with the gross domestic product. We ranked countries and institutions based on the frequency of publications and discovered that Europe, the USA, and China are the leading regions for silicosis research, with the USA and Europe having a stronger influence. Many reports related to artificial stone and denim jean production have been studied through citation analysis, indicating new epidemic trends in silicosis. Besides, silicosis-related diseases and the pathogenesis of silicosis were the research hotspots of silicosis through co-occurrence keyword analysis and outbreak detection. Furthermore, related diseases include coal workers' pneumoconiosis and tuberculosis, while the mechanism of silicosis includes studies on inflammation and fibrosis, oxidative stress, alveolar macrophages, apoptosis, and pathways.

Pollutant-induced pyroptosis in humans and other animals

Pyroptosis is a form of lytic cell death with pro-inflammatory characteristics, induced upon the activation of certain inflammatory caspases by inflammasome complexes such as NLRP3 inflammasome. Gasdermin proteins as the mediators of pyroptosis form cell membrane pores upon activation, which release certain cellular contents into the extracellular space including inflammatory cytokines such as IL-1β and IL-18, and also damage the integrity of the cell membrane. Gasdermins have been implicated in autoimmune and inflammatory diseases, infectious diseases, deafness and cancer. Mostly in the last 2 years, diverse pollutant types including particulate matter, cadmium and polystyrene microplastics were reported to induce pyroptotic cell death in diverse tissues from mammals to birds. In the present study, we review our current understanding of pollutant-induced pyroptosis as well as current knowledge of upstream events leading to pyroptotic cell death upon exposure to pollutants.

Preclinical Mouse Model of Silicosis

Silicosis is an untreatable occupational lung disease caused by chronic inhalation of crystalline silica. Cyclical release and reuptake of silica particles by macrophages and airway epithelial cells causes repeated tissue damage, characterized by widespread inflammation and progressive diffuse fibrosis. While inhalation is the main route of entry for silica particles in humans, most preclinical studies administer silica via the intratracheal route. In vivo mouse models of lung disease are valuable tools required to bridge the translational gap between in vitro cell culture and human disease. This chapter describes a mouse model of silicosis which mimics clinical features of human silicosis, as well as methods for intranasal instillation of silica and disease analysis. Lung tissue can be collected for histological assessment of silica particle distribution, inflammation, structural damage, and fibrosis in sections stained with hematoxylin and eosin or Masson's trichrome. This approach can be extended to other chronic fibrotic lung diseases where inhalation of small damaging particles such as pollutants causes irreversible disease.

The aggravate role of exosomal circRNA11:120406118|12040782 on macrophage pyroptosis through miR-30b-5p/NLRP3 axis in silica-induced lung fibrosis

Silica dust inhalation could lead to silicosis, and there is no specific biomarker for its early diagnosis and no effective treatment due to the lack of research on its pathogenesis. The homeostasis of macrophages was considered to be crucial during the development of silicosis from persistent chronic inflammation to irreversible fibrosis. However, its regulatory mechanism and the communication between macrophages and others are still not clear. Exosomal circRNAs emerge as favorable candidates for cellular communication. Therefore, our study aimed to illustrate the regulatory mechanism of silicosis from the view of exosomal circRNAs. Our study identified a novel exosomal circRNA, circRNA11:120406118|12040782, in the peripheral serum of silicosis patients. Furthermore, the detailed role of circRNA11:120406118|12040782 was investigated both in silicosis mouse model and in silica-stimulated macrophages and fibroblasts. On the one hand, circRNA11:120406118|12040782 was shown to regulate silica-stimulated macrophage pyroptosis through circRNA11:120406118|12040782/miR-30b-5p/NLRP3 network. And this macrophage-derived cirRNA could promote the activation of fibroblasts. On the other hand, overexpressing miR-30b-5p, the crucial component of circRNA11:120406118|12040782/miR-30b-5p/NLRP3 regulatory network, could inhibit pyroptosis and attenuate silica-induced lung inflammation and fibrosis in mice. Our findings suggested that exosomal circRNA11:120406118|12040782 could aggravate NLRP3-mediated macrophages pyroptosis through sponging miR-30b-5p in silicosis development, which provide an experimental basis and shed light on the early diagnosis and treatment of silicosis.

Silica crystals activate toll-like receptors and inflammasomes to promote local and systemic immune responses in zebrafish

Silica crystals are potent activators of the inflammasome that cause a fibrotic lung disease, called silicosis, with no effective treatment available. We report here that injection of silica crystals into the hindbrain ventricle of zebrafish embryos led to the initiation of local and systemic immune responses driven through both Toll-like receptors (TLR)- and inflammasome-dependent signaling pathways, followed by induction of pro-fibrotic markers. Genetic and pharmacological analysis revealed that the Nlrp3 inflammasome regulated silica crystal-induced inflammation and pyroptotic cell death, but not emergency myelopoiesis. In addition, Cxcl8a/Cxcr2-dependent recruitment of myeloid cells to silica crystals was required to promote emergency myelopoiesis and systemic inflammation. The zebrafish model of silicosis developed here shed light onto the molecular mechanisms involved in the activation of the immune system by silica crystals.

The emerging role of epigenetic regulation in the progression of silicosis

Silicosis is one of the most severe occupational diseases worldwide and is characterized by silicon nodules and diffuse pulmonary fibrosis. However, specific treatments for silicosis are still lacking at present. Therefore, elucidating the pathogenesis of silicosis plays a significant guiding role for its treatment and prevention. The occurrence and development of silicosis are accompanied by many regulatory mechanisms, including epigenetic regulation. The main epigenetic regulatory mechanisms of silicosis include DNA methylation, non-coding RNA (ncRNA), and histone modifications. In recent years, the expression and regulation of genes related to silicosis have been explored at epigenetic level to reveal its pathogenesis further, and the identification of aberrant epigenetic markers provides new biomarkers for prediction and diagnosis of silicosis. Here, we summarize the studies on the role of epigenetic changes in the pathogenesis of silicosis to give some clues for finding specific therapeutic targets for silicosis.

Think Beyond Particle Cytotoxicity: When Self-Cellular Components Released After Immunogenic Cell Death Explain Chronic Disease Development

The prolonged perturbation of the immune system following the release of a plethora of self-molecules (known as damage-associated molecular patterns, DAMPs) by stressed or dying cells triggers acute and chronic pathological responses. DAMPs are commonly released after plasma membrane damage or complete rupture due to immunogenic cell death (ICD), upon numerous stressors including infectious and toxic agents. The set of DAMPs released after ICD include mature proinflammatory cytokines and alarmins, but also polymeric macromolecules. These self-intracellular components are recognized by injured and healthy surrounding cells via innate receptors, and induce upregulation of stress-response mechanisms, including inflammation. In this review, by overstepping the simple toxicological evaluation, we apply ICD and DAMP concepts to silica cytotoxicity, providing new insights on the mechanisms driving the progress and/or the exacerbation of certain SiO2–related pathologies. Finally, by proposing self-DNA as new crucial DAMP, we aim to pave the way for the development of innovative and easy-to-perform predictive tests to better identify the hazard of fine and ultrafine silica particles. Importantly, such mechanisms could be extended to nano/micro plastics and diesel particles, providing strategic advice and reports on their health issues.

Non-apoptotic cell death-based cancer therapy: Molecular mechanism, pharmacological modulators, and nanomedicine

As an emerging cancer therapeutic target, non-apoptotic cell death such as ferroptosis, necroptosis and pyroptosis, etc., has revealed significant potential in cancer treatment for bypassing apoptosis to enhance the undermined therapeutic efficacy triggered by apoptosis resistance. A variety of anticancer drugs, synthesized compounds and natural products have been proven recently to induce non-apoptotic cell death and exhibit excellent anti-tumor effects. Moreover, the convergence of nanotechnology with functional materials and biomedicine science has provided tremendous opportunities to construct non-apoptotic cell death-based nanomedicine for innovative cancer therapy. Nanocarriers are not only employed in targeted delivery of non-apoptotic inducers, but also used as therapeutic components to induce non-apoptotic cell death to achieve efficient tumor treatment. This review first introduces the main characteristics, the mechanism and various pharmacological modulators of different non-apoptotic cell death forms, including ferroptosis, necroptosis, pyroptosis, autophagy, paraptosis, lysosomal-dependent cell death, and oncosis. Second, we comprehensively review the latest progresses of nanomedicine that induces various forms of non-apoptotic cell death and focus on the nanomedicine targeting different pathways and components. Furthermore, the combination therapies of non-apoptotic cell death with photothermal therapy, photodynamic therapy, immunotherapy and other modalities are summarized. Finally, the challenges and future perspectives in this regard are also discussed.