Novel Role for Tranilast in Regulating NLRP3 Ubiquitination, Vascular Inflammation, and Atherosclerosis

Unraveling the role of NLRP3 inflammasome in allergic inflammation: implications for novel therapies

Allergic diseases like asthma, allergic rhinitis and dermatitis pose a significant global health burden, driving the search for novel therapies. The NLRP3 inflammasome, a key component of the innate immune system, is implicated in various inflammatory diseases. Upon exposure to allergens, NLRP3 undergoes a two-step activation process (priming and assembly) to form active inflammasomes. These inflammasomes trigger caspase-1 activation, leading to the cleavage of pro-inflammatory cytokines (IL-1β and IL-18) and GSDMD. This process induces pyroptosis and amplifies inflammation. Recent studies in humans and mice strongly suggest a link between the NLRP3 inflammasome, IL-1β, and IL-18, and the development of allergic diseases. However, further research is needed to fully understand NLRP3's specific mechanisms in allergies. This review aims to summarize the latest advances in NLRP3 activation and regulation. We will discuss small molecule drugs and natural products targeting NLRP3 as potential therapeutic strategies for allergic diseases.

Targeting inflammasomes and pyroptosis in retinal diseases-molecular mechanisms and future perspectives

Retinal diseases encompass various conditions associated with sight-threatening immune responses and are leading causes of blindness worldwide. These diseases include age-related macular degeneration, diabetic retinopathy, glaucoma and uveitis. Emerging evidence underscores the vital role of the innate immune response in retinal diseases, beyond the previously emphasized T-cell-driven processes of the adaptive immune system. In particular, pyroptosis, a newly discovered programmed cell death process involving inflammasome formation, has been implicated in the loss of membrane integrity and the release of inflammatory cytokines. Several disease-relevant animal models have provided evidence that the formation of inflammasomes and the induction of pyroptosis in innate immune cells contribute to inflammation in various retinal diseases. In this review article, we summarize current knowledge about the innate immune system and pyroptosis in retinal diseases. We also provide insights into translational targeting approaches, including novel drugs countering pyroptosis, to improve the diagnosis and treatment of retinal diseases.

Tranilast alleviates visceral hypersensitivity and colonic hyperpermeability by suppressing NLRP3 inflammasome activation in irritable bowel syndrome rat models

Visceral hypersensitivity resulting from compromised gut barrier with activated immune system is a key feature of irritable bowel syndrome (IBS). Corticotropin-releasing factor (CRF) and Toll-like receptor 4 (TLR4) activate proinflammatory cytokine signaling to induce these changes, which is one of the mechanisms of IBS. As activation of the NLRP3 inflammasome by lipopolysaccharide (LPS) or TLR4 leads to release interleukin (IL)-1β, the NLRP3 inflammasome may be involved in the pathophysiology of IBS. Tranilast, an anti-allergic drug has been demonstrated to inhibit the NLRP3 inflammasome, and we evaluated the impact of tranilast on visceral hypersensitivity and colonic hyperpermeability induced by LPS or CRF (IBS rat model). Visceral pain threshold caused by colonic balloon distention was measured by monitoring abdominal muscle contractions electrophysiologically. Colonic permeability was determined by quantifying the absorbed Evans blue within the colonic tissue. Colonic protein levels of NLRP3 and IL-1β were assessed by immunoblot or ELISA. Intragastric administration of tranilast (20-200 mg/kg) for 3 days inhibited LPS (1 mg/kg)-induced visceral hypersensitivity and colonic hyperpermeability in a dose-dependent manner. Simultaneously, tranilast also abolished these alterations induced by CRF (50 µg/kg). LPS increased colonic protein levels of NLRP3 and IL-1β, and tranilast inhibited these changes. β-hydroxy butyrate, an NLRP3 inhibitor, also abolished visceral hypersensitivity and colonic hyperpermeability caused by LPS. In contrast, IL-1β induced similar GI alterations to LPS, which were not modified by tranilast. In conclusion, tranilast improved visceral pain and colonic barrier by suppression of the NLRP3 inflammasome in IBS rat models. Tranilast may be useful for IBS treating.

Targeting epigenetic and post-translational modifications regulating pyroptosis for the treatment of inflammatory diseases

Inflammatory diseases, including infectious diseases, diabetes-related diseases, arthritis-related diseases, neurological diseases, digestive diseases, and tumor, continue to threaten human health and impose a significant financial burden despite advancements in clinical treatment. Pyroptosis, a pro-inflammatory programmed cell death pathway, plays an important role in the regulation of inflammation. Moderate pyroptosis contributes to the activation of native immunity, whereas excessive pyroptosis is associated with the occurrence and progression of inflammation. Pyroptosis is complicated and tightly controlled by various factors. Accumulating evidence has confirmed that epigenetic modifications and post-translational modifications (PTMs) play vital roles in the regulation of pyroptosis. Epigenetic modifications, which include DNA methylation and histone modifications (such as methylation and acetylation), and post-translational modifications (such as ubiquitination, phosphorylation, and acetylation) precisely manipulate gene expression and protein functions at the transcriptional and post-translational levels, respectively. In this review, we summarize the major pathways of pyroptosis and focus on the regulatory roles and mechanisms of epigenetic and post-translational modifications of pyroptotic components. We also illustrate these within pyroptosis-associated inflammatory diseases. In addition, we discuss the effects of novel therapeutic strategies targeting epigenetic and post-translational modifications on pyroptosis, and provide prospective insight into the regulation of pyroptosis for the treatment of inflammatory diseases.

Dysregulated cellular metabolism in atherosclerosis: mediators and therapeutic opportunities

Accumulating evidence over the past decades has revealed an intricate relationship between dysregulation of cellular metabolism and the progression of atherosclerotic cardiovascular disease. However, an integrated understanding of dysregulated cellular metabolism in atherosclerotic cardiovascular disease and its potential value as a therapeutic target is missing. In this Review, we (1) summarize recent advances concerning the role of metabolic dysregulation during atherosclerosis progression in lesional cells, including endothelial cells, vascular smooth muscle cells, macrophages and T cells; (2) explore the complexity of metabolic cross-talk between these lesional cells; (3) highlight emerging technologies that promise to illuminate unknown aspects of metabolism in atherosclerosis; and (4) suggest strategies for targeting these underexplored metabolic alterations to mitigate atherosclerosis progression and stabilize rupture-prone atheromas with a potential new generation of cardiovascular therapeutics.

"How to Release or Not Release, That Is the Question." A Review of Interleukin-1 Cellular Release Mechanisms in Vascular Inflammation

Cardiovascular disease remains the leading cause of death worldwide, characterized by atherosclerotic activity within large and medium-sized arteries. Inflammation has been shown to be a primary driver of atherosclerotic plaque formation, with interleukin-1 (IL-1) having a principal role. This review focuses on the current state of knowledge of molecular mechanisms of IL-1 release from cells in atherosclerotic plaques. A more in-depth understanding of the process of IL-1's release into the vascular environment is necessary for the treatment of inflammatory disease processes, as the current selection of medicines being used primarily target IL-1 after it has been released. IL-1 is secreted by several heterogenous mechanisms, some of which are cell type-specific and could provide further specialized targets for therapeutic intervention. A major unmet challenge is to understand the mechanism before and leading to IL-1 release, especially by cells in atherosclerotic plaques, including endothelial cells, vascular smooth muscle cells, and macrophages. Data so far indicate a heterogeneity of IL-1 release mechanisms that vary according to cell type and are stimulus-dependent. Unraveling this complexity may reveal new targets to block excess vascular inflammation.

LUBAC promotes angiogenesis and lung tumorigenesis by ubiquitinating and antagonizing autophagic degradation of HIF1α

Hypoxia-inducible factor 1 (HIF1) is critically important for driving angiogenesis and tumorigenesis. Linear ubiquitin chain assembly complex (LUBAC), the only known ubiquitin ligase capable of catalyzing protein linear ubiquitination to date, is implicated in cell signaling and associated with cancers. However, the role and mechanism of LUBAC in regulating the expression and function of HIF1α, the labile subunit of HIF1, remain to be elucidated. Herein we showed that LUBAC increases HIF1α protein expression in cultured cells and tissues of human lung cancer and enhances HIF1α DNA-binding and transcriptional activities, which are dependent upon LUBAC enzymatic activity. Mechanistically, LUBAC increases HIF1α stability through antagonizing HIF1α decay by the chaperone-mediated autophagy (CMA)-lysosome pathway, thereby potentiating HIF1α activity. We further demonstrated that HIF1α selectively interacts with HOIP (the catalytic subunit of LUBAC) primarily in the cytoplasm. LUBAC catalyzes linear ubiquitination of HIF1α at lysine 362. Linear ubiquitination shields HIF1α from interacting with heat-shock cognate protein of 70 kDa and lysosome-associated membrane protein type 2 A, two components of CMA. Consequently, linear ubiquitination confers protection against CMA-mediated destruction of HIF1α, increasing HIF1α stability and activity. We found that prolyl hydroxylation is not a perquisite for LUBAC's effects on HIF1α. Functionally, LUBAC facilitates proliferation, clonogenic formation, invasion and migration of lung cancer cells. LUBAC also boosts angiogenesis and exacerbates lung cancer growth in mice, which are greatly compromised by inhibition of HIF1α. This work provides novel mechanistic insights into the role of LUBAC in regulating HIF1α homeostasis, tumor angiogenesis and tumorigenesis of lung cancer, making LUBAC an attractive therapeutic target for cancers.

The role of inflammasomes in human diseases and their potential as therapeutic targets

Inflammasomes are large protein complexes that play a major role in sensing inflammatory signals and triggering the innate immune response. Each inflammasome complex has three major components: an upstream sensor molecule that is connected to a downstream effector protein such as caspase-1 through the adapter protein ASC. Inflammasome formation typically occurs in response to infectious agents or cellular damage. The active inflammasome then triggers caspase-1 activation, followed by the secretion of pro-inflammatory cytokines and pyroptotic cell death. Aberrant inflammasome activation and activity contribute to the development of diabetes, cancer, and several cardiovascular and neurodegenerative disorders. As a result, recent research has increasingly focused on investigating the mechanisms that regulate inflammasome assembly and activation, as well as the potential of targeting inflammasomes to treat various diseases. Multiple clinical trials are currently underway to evaluate the therapeutic potential of several distinct inflammasome-targeting therapies. Therefore, understanding how different inflammasomes contribute to disease pathology may have significant implications for developing novel therapeutic strategies. In this article, we provide a summary of the biological and pathological roles of inflammasomes in health and disease. We also highlight key evidence that suggests targeting inflammasomes could be a novel strategy for developing new disease-modifying therapies that may be effective in several conditions.

Targeting NLRP3 inflammasome for neurodegenerative disorders

Neuroinflammation is a key pathological feature in neurological diseases, including Alzheimer's disease (AD). The nucleotide-binding domain leucine-rich repeat-containing proteins (NLRs) belong to the pattern recognition receptors (PRRs) family that sense stress signals, which play an important role in inflammation. As a member of NLRs, the NACHT, LRR and PYD domains-containing protein 3 (NLRP3) is predominantly expressed in microglia, the principal innate immune cells in the central nervous system (CNS). Microglia release proinflammatory cytokines to cause pyroptosis through activating NLRP3 inflammasome. The active NLRP3 inflammasome is involved in a variety of neurodegenerative diseases (NDs). Recent studies also indicate the key role of neuronal NLRP3 in the pathogenesis of neurological disorders. In this article, we reviewed the mechanisms of NLRP3 expression and activation and discussed the role of active NLRP3 inflammasome in the pathogenesis of NDs, particularly focusing on AD. The studies suggest that targeting NLRP3 inflammasome could be a novel approach for the disease modification.

The purinergic receptor P2X7 and the NLRP3 inflammasome are druggable host factors required for SARS-CoV-2 infection

Purinergic receptors and NOD-like receptor protein 3 (NLRP3) inflammasome regulate inflammation and viral infection, but their effects on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection remain poorly understood. Here, we report that the purinergic receptor P2X7 and NLRP3 inflammasome are cellular host factors required for SARS-CoV-2 infection. Lung autopsies from patients with severe coronavirus disease 2019 (COVID-19) reveal that NLRP3 expression is increased in host cellular targets of SARS-CoV-2 including alveolar macrophages, type II pneumocytes and syncytia arising from the fusion of infected macrophages, thus suggesting a potential role of NLRP3 and associated signaling pathways to both inflammation and viral replication. In vitro studies demonstrate that NLRP3-dependent inflammasome activation is detected upon macrophage abortive infection. More importantly, a weak activation of NLRP3 inflammasome is also detected during the early steps of SARS-CoV-2 infection of epithelial cells and promotes the viral replication in these cells. Interestingly, the purinergic receptor P2X7, which is known to control NLRP3 inflammasome activation, also favors the replication of D614G and alpha SARS-CoV-2 variants. Altogether, our results reveal an unexpected relationship between the purinergic receptor P2X7, the NLRP3 inflammasome and the permissiveness to SARS-CoV-2 infection that offers novel opportunities for COVID-19 treatment.

Research progress of NLRP3 inflammasome and its inhibitors with aging diseases

In recent years, a new target closely linked to a variety of diseases has appeared in the researchers' vision, which is the NLRP3 inflammasome. With the deepening of the study of NLRP3 inflammasome, it was found that it plays an extremely important role in a variety of physiological pathological processes, and NLRP3 inflammasome was also found to be associated with some age-related diseases. It is associated with the development of insulin resistance, Alzheimer's disease, Parkinson's, cardiovascular aging, hearing and vision loss. At present, the only clinical approach to the treatment of NLRP3 inflammasome-related diseases is to use anti-IL-1β antibodies, but NLRP3-specific inhibitors may be better than the IL-1β antibodies. This article reviews the relationship between NLRP3 inflammasome and aging diseases: summarizes some of the relevant experimental results reported in recent years, and introduces the biological signals or pathways closely related to the NLRP3 inflammasome in a variety of aging diseases, and also introduces some promising small molecule inhibitors of NLRP3 inflammasome for clinical treatment, such as: ZYIL1, DFV890 and OLT1177, they have excellent pharmacological effects and good pharmacokinetics.

Inflammasome: structure, biological functions, and therapeutic targets

Inflammasomes are a group of protein complex located in cytoplasm and assemble in response to a wide variety of pathogen-associated molecule patterns, damage-associated molecule patterns, and cellular stress. Generally, the activation of inflammasomes will lead to maturation of proinflammatory cytokines and pyroptotic cell death, both associated with inflammatory cascade amplification. A sensor protein, an adaptor, and a procaspase protein interact through their functional domains and compose one subunit of inflammasome complex. Under physiological conditions, inflammasome functions against pathogen infection and endogenous dangers including mtROS, mtDNA, and so on, while dysregulation of its activation can lead to unwanted results. In recent years, advances have been made to clarify the mechanisms of inflammasome activation, the structural details of them and their functions (negative/positive) in multiple disease models in both animal models and human. The wide range of the stimuli makes the function of inflammasome diverse and complex. Here, we review the structure, biological functions, and therapeutic targets of inflammasomes, while highlight NLRP3, NLRC4, and AIM2 inflammasomes, which are the most well studied. In conclusion, this review focuses on the activation process, biological functions, and structure of the most well-studied inflammasomes, summarizing and predicting approaches for disease treatment and prevention with inflammasome as a target. We aim to provide fresh insight into new solutions to the challenges in this field.

Posttranslational modifications of NLRP3 and their regulatory roles in inflammasome activation

The NACHT, LRR, and PYD domains-containing protein 3 (NLRP3) inflammasome is a multimolecular complex that plays a fundamental role in inflammation. Optimal activation of NLRP3 inflammasome is crucial for host defense against pathogens and the maintenance of immune homeostasis. Aberrant NLRP3 inflammasome activity has been implicated in various inflammatory diseases. Posttranslational modifications (PTMs) of NLRP3, a key inflammasome sensor, play critical roles in directing inflammasome activation and controlling the severity of inflammation and inflammatory diseases, such as arthritis, peritonitis, inflammatory bowel disease, atherosclerosis, and Parkinson's disease. Various NLRP3 PTMs, including phosphorylation, ubiquitination, and SUMOylation, could direct inflammasome activation and control inflammation severity by affecting the protein stability, ATPase activity, subcellular localization, and oligomerization of NLRP3 as well as the association between NLRP3 and other inflammasome components. Here, we provide an overview of the PTMs of NLRP3 and their roles in controlling inflammation and summarize potential anti-inflammatory drugs targeting NLRP3 PTMs.

Inflammasomes in Atherosclerosis-From Pathophysiology to Treatment

Atherosclerosis, a chronic inflammatory disease characterized by arterial plaque accumulation, remains a significant global health challenge. In recent years, inflammasomes, the intracellular multiprotein complexes crucial for initiating innate immune responses, have emerged as key players in atherosclerosis pathophysiology. This review article aims to provide a comprehensive overview of the current understanding of inflammasome activation and its impact on atherosclerosis development and progression. We explore the intricate interplay between traditional cardiovascular risk factors and inflammasome activation, leading to the perpetuation of inflammatory cascades that drive plaque formation and instability. The review focuses on the molecular mechanisms underlying inflammasome activation, including the role of pattern recognition receptors and cytokines in this process. Moreover, we discuss the contribution of inflammasomes to endothelial dysfunction, foam cell formation, and vascular inflammation. Additionally, recent advances in therapeutic strategies targeting inflammasomes are examined, including pharmacological agents and potential immunomodulatory approaches. By collating and analyzing the current evidence, this review provides valuable insights into the potential of inflammasome-targeted therapies for atherosclerosis management and treatment. Understanding the pivotal role of inflammasomes in atherosclerosis pathophysiology offers promising prospects for developing effective and personalized therapeutic interventions that can mitigate the burden of this prevalent cardiovascular disorder and improve patient outcomes.

Insights into the Role of Inflammation in the Management of Atherosclerosis

Atherosclerosis is the biological basis of ischemic heart disease and ischemic stroke, the leading causes of death in the world. After decades of studies, the understanding of atherosclerosis has evolved dramatically, and inflammation has been recognized as one of the most relevant pillars in all phases of atherosclerotic disease. Nevertheless, only recently, the trial CANTOS, and subsequent outcome studies with colchicine, finally provided proof-of-concept evidence that anti-inflammatory therapies were able to reduce cardiovascular events with no influence on lipid levels. These landmark studies inaugurated an era of clinical and pre-clinical studies of immunomodulatory strategies focused on reduction of cardiovascular risk. Although there are promising results in the field, selection of the most appropriate immunomodulatory therapy and identification of patients who could benefit the most, are still enormous challenges. Further research is imperative before we can finally advance towards regular use of anti-inflammatory agents to reduce atherosclerotic events in our clinical practice.

An update on the role of TRIM/NLRP3 signaling pathway in atherosclerosis

Atherosclerosis (AS) is a chronic inflammatory disease of large and medium arteries that includes lipid metabolism disorder and recruitment of immune cells to the artery wall. An increasing number of studies have confirmed that inflammasome over-activation is associated with the onset and progression of atherosclerosis. The NLRP3 inflammasome, in particular, has been proven to increase the incidence rate of cardiovascular diseases (CVD) by promoting pro-inflammatory cytokine release and reducing plaque stability. The strict control of inflammasome and prevention of excessive inflammatory reactions have been the research focus of inflammatory diseases. Tripartite motif (TRIM) is a protein family with a conservative structure and rapid evolution. Several studies have demonstrated the TRIM family's regulatory role in mediating inflammation. This review aims to clarify the relationship between TRIMs and NLRP3 inflammasome and provide insights for future research and treatment discovery.

Tranilast reduces cardiomyocyte injury induced by ischemia‑reperfusion via Nrf2/HO‑1/NF‑κB signaling

Tranilast, a synthetic derivative of a tryptophan metabolite, can be used to treat heart diseases. However, the specific mechanism underlying the effect of tranilast on ischemia-reperfusion (I/R) injury-induced cardiomyocyte apoptosis remains unclear. Therefore, the present study aimed to determine if tranilast could attenuate I/R-induced cardiomyocyte injury. A hypoxia/reoxygenation (H/R) model of H9c2 cardiomyocytes was established to simulate I/R-induced cardiomyocyte injury. The viability, apoptosis, inflammation and oxidative stress in H/R-induced H9c2 cells following treatment with tranilast were evaluated by Cell Counting Kit-8 and TUNEL assay. Commercially available kits were used to detect the levels of inflammatory markers and oxidative stress indicators. In addition, the expression levels of the apoptosis- and nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1)/NF-κB signalling pathway-associated proteins were detected by western blotting. The levels of reactive oxygen species were determined using 2',7'-dichlorofluorescin diacetate assay kit. The viability of H9c2 cells was decreased following induction with H/R. However, treatment with tranilast increased viability while decreasing apoptosis, oxidative stress and inflammatory response in H/R-induced H9c2 cells by activating Nrf2/HO-1/NF-κB signalling. Furthermore, treatment with ML-385, an Nrf2 inhibitor, reversed the effects of tranilast on H/R-induced H9c2 cells. In conclusion, the results of the present study suggested that tranilast could attenuate I/R-induced cardiomyocyte injury via the Nrf2/HO-1/NF-κB signalling pathway.

The Role of Post-Translational Modifications in Regulation of NLRP3 Inflammasome Activation

Pathogen-associated molecular patterns (PAMPs) and danger-associated molecular patterns (DAMPs) induce NLRP3 inflammasome activation, and subsequent formation of active caspase-1 as well as the maturation of interleukin-1β (IL-1β) and gasdermin D (GSDMD), mediating the occurrence of pyroptosis and inflammation. Aberrant NLRP3 inflammasome activation causes a variety of diseases. Therefore, the NLRP3 inflammasome pathway is a target for prevention and treatment of relative diseases. Recent studies have suggested that NLRP3 inflammasome activity is closely associated with its post-translational modifications (PTMs). This review focuses on PTMs of the components of the NLRP3 inflammasome and the resultant effects on regulation of its activity to provide references for the exploration of the mechanisms by which the NLRP3 inflammasome is activated and controlled.

Metaflammation in glucolipid metabolic disorders: Pathogenesis and treatment

The public health issue of glucolipid metabolic disorders (GLMD) has grown significantly, posing a grave threat to human wellness. Its prevalence is rising yearly and tends to affect younger people. Metaflammation is an important mechanism regulating body metabolism. Through a complicated multi-organ crosstalk network involving numerous signaling pathways such as NLRP3/caspase-1/IL-1, NF-B, p38 MAPK, IL-6/STAT3, and PI3K/AKT, it influences systemic metabolic regulation. Numerous inflammatory mediators are essential for preserving metabolic balance, but more research is needed to determine how they contribute to the co-morbidities of numerous metabolic diseases. Whether controlling the inflammatory response can influence the progression of GLMD determines the therapeutic strategy for such diseases. This review thoroughly examines the role of metaflammation in GLMD and combs the research progress of related therapeutic approaches, including inflammatory factor-targeting drugs, traditional Chinese medicine (TCM), and exercise therapy. Multiple metabolic diseases, including diabetes, non-alcoholic fatty liver disease (NAFLD), cardiovascular disease, and others, respond therapeutically to anti-inflammatory therapy on the whole. Moreover, we emphasize the value and open question of anti-inflammatory-based means for treating GLMD.

Involvement of inflammasomes in tumor microenvironment and tumor therapies

Inflammasomes are macromolecular platforms formed in response to damage-associated molecular patterns (DAMPs) and pathogen-associated molecular patterns, whose formation would cause maturation of interleukin-1 (IL-1) family members and gasdermin D (GSDMD), leading to IL-1 secretion and pyroptosis respectively. Several kinds of inflammasomes detecting different types of dangers have been found. The activation of inflammasomes is regulated at both transcription and posttranscription levels, which is crucial in protecting the host from infections and sterile insults. Present findings have illustrated that inflammasomes are involved in not only infection but also the pathology of tumors implying an important link between inflammation and tumor development. Generally, inflammasomes participate in tumorigenesis, cell death, metastasis, immune evasion, chemotherapy, target therapy, and radiotherapy. Inflammasome components are upregulated in some tumors, and inflammasomes can be activated in cancer cells and other stromal cells by DAMPs, chemotherapy agents, and radiation. In some cases, inflammasomes inhibit tumor progression by initiating GSDMD-mediated pyroptosis in cancer cells and stimulating IL-1 signal-mediated anti-tumor immunity. However, IL-1 signal recruits immunosuppressive cell subsets in other cases. We discuss the conflicting results and propose some possible explanations. Additionally, we also summarize interventions targeting inflammasome pathways in both preclinical and clinical stages. Interventions targeting inflammasomes are promising for immunotherapy and combination therapy.

Inflammation and Heart Failure: Searching for the Enemy-Reaching the Entelechy

The pivotal role of inflammation in the pathophysiology of heart-failure (HF) development and progression has long been recognized. High blood levels of pro-inflammatory and inflammatory markers are present and associated with adverse outcomes in patients with HF. In addition, there seems to be an interrelation between inflammation and neurohormonal activation, the cornerstone of HF pathophysiology and management. However, clinical trials involving anti-inflammatory agents have shown inconclusive or even contradictory results in improving HF outcomes. In the present review, we try to shed some light on the reciprocal relationship between inflammation and HF in an attempt to identify the central regulating factors, such as inflammatory cells and soluble mediators and the related inflammatory pathways as potential therapeutic targets.

Chronic kidney disease and NLRP3 inflammasome: Pathogenesis, development and targeted therapeutic strategies

Chronic kidney disease (CKD) is a global health concern and public health priority. The condition often involves inflammation due to the accumulation of toxins and the reduced clearance of inflammatory cytokines, leading to gradual loss of kidney function. Because of the tremendous burden of CKD, finding effective treatment strategies against inflammation is crucial. Substantial evidence suggests an association between kidney disease and the inflammasome. As a well-known multiprotein signaling complex, the NLR family pyrin domain containing 3 (NLRP3) inflammasome plays an important role in inducing renal inflammation and fibrosis. Small molecule inhibitors targeting the NLRP3 inflammasome are potential agents for the treatment of CKD.The NLRP3 inflammasome activation amplifies the inflammation response, promoting pyroptotic cell death. Thus, it may contribute to the onset and progression of CKD, but the mechanism behind inflammasome activation in CKD remains obscure.In this review, we summarized recent findings on the role of the NLRP3 inflammasome in CKD and new strategies targeting the NLRP3 inflammasome.

LCZ696 protects against doxorubicin-induced cardiotoxicity by inhibiting ferroptosis via AKT/SIRT3/SOD2 signaling pathway activation

Doxorubicin (DOX) is an effective and widely used anticancer drug but has limited clinical applicability because of its cardiotoxicity. Ferroptosis plays a key role in DOX-induced cardiac damage and cardiomyocyte cell death. The inhibition of ferroptosis reverses DOX-induced cardiotoxicity (DIC). LCZ696, a first-in-class angiotensin receptor neprilysin inhibitor, protects against DIC. However, the mechanism of action of LCZ696, especially its effect on ferroptosis, is incompletely understood. This study investigates the cardioprotective effects of LCZ696 on DIC in vivo and in vitro.Cardiotoxicity was induced in Wistar rats by tail intravenous injection of 2.5 mg/kg DOX once a week for six weeks. Rats and H9c2 cells were treated with or without LCZ696 to determine the cardioprotective role and underlying mechanisms of LCZ696 against DIC. To assess the role of SIRT3 and correlated pathways in ferroptosis, SIRT3 knockout was performed using lentiviral vectors, and AKT was inhibited with LY294002. LCZ696 significantly attenuated DIC by decreasing the concentrations of lipid reactive oxygen species and malondialdehyde and increasing the levels of glutathione peroxidase-4 and reduced glutathione in cells and heart tissues. Moreover, LCZ696 remodeled myocardial structures and improved heart ventricular function in DOX-treated rats. LCZ696 treatment increased SIRT3 expression and deacetylated its target gene SOD2, and these changes were mediated by AKT activation. SIRT3 knockdown and AKT inhibition induced lipid peroxidation and reduced the protective effect of LCZ696 in H9c2 cells. Collectively,LCZ696 prevents DIC by inhibiting ferroptosis via AKT/SIRT3/SOD2 signaling pathway activation. Thus, LZC696 is a potential therapeutic strategy for DIC.

The Role of NLRP3 Inflammasome in Diabetic Cardiomyopathy and Its Therapeutic Implications

Diabetic cardiomyopathy (DCM) is a serious complication of diabetes mellitus (DM). However, the precise molecular mechanisms remain largely unclear, and it is still a challenging disease to diagnose and treat. The nucleotide-binding oligomerization domain and leucine-rich repeat pyrin 3 domain (NLRP3) inflammasome is a critical part of the innate immune system in the host to defend against endogenous danger and pathogenic microbial infections. Dysregulated NLRP3 inflammasome activation results in the overproduction of cytokines, primarily IL-1β and IL-18, and eventually, inflammatory cell death-pyroptosis. A series of studies have indicated that NLRP3 inflammasome activation participates in the development of DCM, and that corresponding interventions could mitigate disease progression. Accordingly, this narrative review is aimed at briefly summarizing the cell-specific role of the NLRP3 inflammasome in DCM and provides novel insights into developing DCM therapeutic strategies targeting the NLRP3 inflammasome.

The NLRP3 Inflammasome as a Novel Therapeutic Target for Cardiac Fibrosis

Cardiac fibrosis often has adverse cardiovascular effects, including heart failure, sudden death, and malignant arrhythmias. However, there is no targeted therapy for cardiac fibrosis. Inflammation is known to play a crucial role in the disorder, and the NLR pyrin domain-containing-3 (NLRP3) inflammasome is closely associated with innate immunity. Therefore, further understanding the pathophysiological role of the inflammasome in cardiac fibrosis may provide novel strategies for the prevention and treatment of the disorder. The aim of this review was to summarize the present knowledge of NLRP3 inflammasome-related mechanisms underlying cardiac fibrosis and to suggest potential targeted therapy that could be used to treat the condition.

Spotlight on pyroptosis: role in pathogenesis and therapeutic potential of ocular diseases

Pyroptosis is a programmed cell death characterized by swift plasma membrane disruption and subsequent release of cellular contents and pro-inflammatory mediators (cytokines), including IL‐1β and IL‐18. It differs from other types of programmed cell death such as apoptosis, autophagy, necroptosis, ferroptosis, and NETosis in terms of its morphology and mechanism. As a recently discovered form of cell death, pyroptosis has been demonstrated to be involved in the progression of multiple diseases. Recent studies have also suggested that pyroptosis is linked to various ocular diseases. In this review, we systematically summarized and discussed recent scientific discoveries of the involvement of pyroptosis in common ocular diseases, including diabetic retinopathy, age-related macular degeneration, AIDS-related human cytomegalovirus retinitis, glaucoma, dry eye disease, keratitis, uveitis, and cataract. We also organized new and emerging evidence suggesting that pyroptosis signaling pathways may be potential therapeutic targets in ocular diseases, hoping to provide a summary of overall intervention strategies and relevant multi-dimensional evaluations for various ocular diseases, as well as offer valuable ideas for further research and development from the perspective of pyroptosis.

Novel role for caspase 1 inhibitor VX765 in suppressing NLRP3 inflammasome assembly and atherosclerosis via promoting mitophagy and efferocytosis

Atherosclerosis is a maladaptive chronic inflammatory disease, which remains the leading cause of death worldwide. The NLRP3 inflammasome constitutes a major driver of atherosclerosis, yet the mechanism of action is poorly understood. Mitochondrial dysfunction is essential for NLRP3 inflammasome activation. However, whether activated NLRP3 inflammasome exacerbates mitochondrial dysfunction remains to be further elucidated. Herein, we sought to address these issues applying VX765, a well-established inhibitor of caspase 1. VX765 robustly restrains caspase 1-mediated interleukin-1β production and gasdermin D processing. Our study assigned VX765 a novel role in antagonizing NLRP3 inflammasome assembly and activation. VX765 mitigates mitochondrial damage induced by activated NLRP3 inflammasome, as evidenced by decreased mitochondrial ROS production and cytosolic release of mitochondrial DNA. VX765 blunts caspase 1-dependent cleavage and promotes mitochondrial recruitment and phosphorylation of Parkin, a key mitophagy regulator. Functionally, VX765 facilitates mitophagy, efferocytosis and M2 polarization of macrophages. It also impedes foam cell formation, migration and pyroptosis of macrophages. VX765 boosts autophagy, promotes efferocytosis, and alleviates vascular inflammation and atherosclerosis in both ApoE^-/- and Ldlr^-/- mice. However, these effects of VX765 were abrogated upon ablation of Nlrp3 in ApoE^-/- mice. This work provides mechanistic insights into NLRP3 inflammasome assembly and this inflammasome in dictating atherosclerosis. This study highlights that manipulation of caspase 1 paves a new avenue to treatment of atherosclerotic cardiovascular disease.

Tranilast attenuates lipopolysaccharide‑induced lung injury via the CXCR4/JAK2/STAT3 signaling pathway

It has been reported that the expression of C-X-C motif chemokine receptor 4 (CXCR4) is increased in patients with lung injury, while CXCR4 downregulation can improve sepsis-induced lung injury. Previous studies have shown that tranilast can inhibit CXCR4 mRNA expression. Therefore, the present study aimed to investigate whether tranilast could protect against lipopolysaccharide (LPS)-induced lung injury via the CXCR4/Janus kinase 2 (JAK2)/STAT3 signaling pathway. A Cell Counting Kit-8 assay was performed to evaluate the effect of different concentrations of tranilast on the viability of LPS-induced BEAS-2B cells. The mRNA and protein expression levels of the inflammatory factors, TNFα, IL-1β, IL-6, cytochrome c oxidase subunit II and inducible nitric oxide synthase were detected using reverse transcription-quantitative PCR and western blot analysis, respectively. In addition, the cell apoptosis rate and the expression levels of apoptosis-related proteins were analyzed using a TUNEL staining assay and western blot analysis, respectively. The expression levels of the CXCR4/JAK2/STAT3 signaling pathway-related proteins were also determined using western blot analysis. Furthermore, the effects of tranilast on cell viability, inflammation and apoptosis were also evaluated in LPS-stimulated BEAS-2B cells following CXCR4 overexpression, which were pre-treated with tranilast. The results demonstrated that tranilast could alleviate LPS-induced cell viability, the secretion of inflammatory cytokines and cell apoptosis. In addition, cell treatment with tranilast inhibited the expression of CXCR4/JAK2/STAT3 signaling-related proteins in LPS-induced BEAS-2B cells. Following CXCR4 overexpression, the alleviating effect of tranilast on cell viability, inflammatory response and apoptosis was notably attenuated. Overall, the current study suggested that tranilast could attenuate LPS-induced lung injury via the CXCR4/JAK2/STAT3 signaling pathway, suggesting that tranilast could be considered as a promising agent for treating sepsis-induced acute lung injury.

The Role of NLRP3 Inflammasome in Alzheimer’s Disease and Potential Therapeutic Targets

Alzheimer’s disease (AD) is a common age-related neurodegenerative disease characterized by progressive cognitive dysfunction and behavioral impairment. The typical pathological characteristics of AD are extracellular senile plaques composed of amyloid ß (Aβ) protein, intracellular neurofibrillary tangles formed by the hyperphosphorylation of the microtubule-associated protein tau, and neuron loss. In the past hundred years, although human beings have invested a lot of manpower, material and financial resources, there is no widely recognized drug for the effective prevention and clinical cure of AD in the world so far. Therefore, evaluating and exploring new drug targets for AD treatment is an important topic. At present, researchers have not stopped exploring the pathogenesis of AD, and the views on the pathogenic factors of AD are constantly changing. Multiple evidence have confirmed that chronic neuroinflammation plays a crucial role in the pathogenesis of AD. In the field of neuroinflammation, the nucleotide-binding oligomerization domain-like receptor pyrin domain-containing 3 (NLRP3) inflammasome is a key molecular link in the AD neuroinflammatory pathway. Under the stimulation of Aβ oligomers and tau aggregates, it can lead to the assembly and activation of NLRP3 inflammasome in microglia and astrocytes in the brain, thereby causing caspase-1 activation and the secretion of IL-1β and IL-18, which ultimately triggers the pathophysiological changes and cognitive decline of AD. In this review, we summarize current literatures on the activation of NLRP3 inflammasome and activation-related regulation mechanisms, and discuss its possible roles in the pathogenesis of AD. Moreover, focusing on the NLRP3 inflammasome and combining with the upstream and downstream signaling pathway-related molecules of NLRP3 inflammasome as targets, we review the pharmacologically related targets and various methods to alleviate neuroinflammation by regulating the activation of NLRP3 inflammasome, which provides new ideas for the treatment of AD.

Targeting the Inflammasome in Cardiovascular Disease

•

Development of cardiovascular disease and inflammation are heavily intertwined, and inflammasome activation is thought play an important role in this interaction.

•

This review provides an overview of preclinical and clinical studies supporting inflammasomes as a therapeutic target in atherosclerosis and heart failure.

•

Future studies exploring direct inflammasome inhibition, either NLRP3 or the lesser-studied inflammasomes, are also discussed.

The pathogenesis of cardiovascular disease (CVD) is complex and multifactorial, and inflammation plays a central role. Inflammasomes are multimeric protein complexes that are activated in a 2-step manner in response to infection or tissue damage. Upon activation the proinflammatory cytokines, interleukins-1β and -18 are released. In the last decade, the evidence that inflammasome activation plays an important role in CVD development became stronger. We discuss the role of different inflammasomes in the pathogenesis of CVD, focusing on atherosclerosis and heart failure. This review also provides an overview of existing experimental studies and clinical trials on inflammasome inhibition as a therapeutic target in these disorders.

Spotlight on NLRP3 Inflammasome: Role in Pathogenesis and Therapies of Atherosclerosis

Inflammation is an intricate biological response of body tissues to detrimental stimuli. Cardiovascular disease (CVD) is the leading cause of death worldwide, and inflammation is well documented to play a role in the development of CVD, especially atherosclerosis (AS). Emerging evidence suggests that activation of the NOD-like receptor (NLR) family and the pyridine-containing domain 3 (NLRP3) inflammasome is instrumental in inflammation and may result in AS. The NLRP3 inflammasome acts as a molecular platform that triggers the activation of caspase-1 and the cleavage of pro-interleukin (IL)-1β, pro-IL-18, and gasdermin D (GSDMD). The cleaved GSDMD forms pores in the cell membrane and initiates pyroptosis, inducing cell death and the discharge of intracellular pro-inflammatory factors. Hence, the NLRP3 inflammasome is a promising target for anti-inflammatory therapy against AS. In this review, we systematically summarized the current understanding of the activation mechanism of NLRP3 inflammasome, and the pathological changes in AS involving NLRP3. We also discussed potential therapeutic strategies targeting NLRP3 inflammasome to combat AS.

NLRP3 Ubiquitination-A New Approach to Target NLRP3 Inflammasome Activation

In response to diverse pathogenic and danger signals, the cytosolic activation of the NLRP3 (NOD-, LRR-, and pyrin domain-containing (3)) inflammasome complex is a critical event in the maturation and release of some inflammatory cytokines in the state of an inflammatory response. After activation of the NLRP3 inflammasome, a series of cellular events occurs, including caspase 1-mediated proteolytic cleavage and maturation of the IL-1β and IL-18, followed by pyroptotic cell death. Therefore, the NLRP3 inflammasome has become a prime target for the resolution of many inflammatory disorders. Since NLRP3 inflammasome activation can be triggered by a wide range of stimuli and the activation process occurs in a complex, it is difficult to target the NLRP3 inflammasome. During the activation process, various post-translational modifications (PTM) of the NLRP3 protein are required to form a complex with other components. The regulation of ubiquitination and deubiquitination of NLRP3 has emerged as a potential therapeutic target for NLRP3 inflammasome-associated inflammatory disorders. In this review, we discuss the ubiquitination and deubiquitination system for NLRP3 inflammasome activation and the inhibitors that can be used as potential therapeutic agents to modulate the activation of the NLRP3 inflammasome.

Anti-inflammatory and Immunomodulatory Therapies in Atherosclerosis

Hypercholesterolemia is a major risk factor in atherosclerosis development and lipid-lowering drugs (i.e., statins) remain the treatment of choice. Despite effective reduction of LDL cholesterol in patients, a residual cardiovascular risk persists in some individuals, highlighting the need for further therapeutic intervention. Recently, the CANTOS trial paved the way toward the development of specific therapies targeting inflammation, a key feature in atherosclerosis progression. The pre-existence of multiple drugs modulating both innate and adaptive immune responses has significantly accelerated the number of translational studies applying these drugs to atherosclerosis. Additional preclinical research has led to the discovery of new therapeutic targets, offering promising perspectives for the treatment and prevention of atherosclerosis. Currently, both drugs with selective targeting and broad unspecific anti-inflammatory effects have been tested. In this chapter, we aim to give an overview of current advances in immunomodulatory treatment approaches for atherosclerotic cardiovascular diseases.

NLRP3 Inflammasome: A Promising Therapeutic Target for Drug-Induced Toxicity

Drug-induced toxicity, which impairs human organ function, is a serious problem during drug development that hinders the clinical use of many marketed drugs, and the underlying mechanisms are complicated. As a sensor of infections and external stimuli, nucleotide-binding oligomerization domain (NOD)-like receptor family pyrin domain containing 3 (NLRP3) inflammasome plays a key role in the pathological process of various diseases. In this review, we specifically focused on the role of NLRP3 inflammasome in drug-induced diverse organ toxicities, especially the hepatotoxicity, nephrotoxicity, and cardiotoxicity. NLRP3 inflammasome is involved in the initiation and deterioration of drug-induced toxicity through multiple signaling pathways. Therapeutic strategies via inhibiting NLRP3 inflammasome for drug-induced toxicity have made significant progress, especially in the protective effects of the phytochemicals. Growing evidence collected in this review indicates that NLRP3 is a promising therapeutic target for drug-induced toxicity.

Vascular Stress Signaling in Hypertension

Cells respond to stress by activating a variety of defense signaling pathways, including cell survival and cell death pathways. Although cell survival signaling helps the cell to recover from acute insults, cell death or senescence pathways induced by chronic insults can lead to unresolved pathologies. Arterial hypertension results from chronic physiological maladaptation against various stressors represented by abnormal circulating or local neurohormonal factors, mechanical stress, intracellular accumulation of toxic molecules, and dysfunctional organelles. Hypertension and aging share common mechanisms that mediate or prolong chronic cell stress, such as endoplasmic reticulum stress and accumulation of protein aggregates, oxidative stress, metabolic mitochondrial stress, DNA damage, stress-induced senescence, and proinflammatory processes. This review discusses common adaptive signaling mechanisms against these stresses including unfolded protein responses, antioxidant response element signaling, autophagy, mitophagy, and mitochondrial fission/fusion, STING (signaling effector stimulator of interferon genes)-mediated responses, and activation of pattern recognition receptors. The main molecular mechanisms by which the vasculature copes with hypertensive and aging stressors are presented and recent advancements in stress-adaptive signaling mechanisms as well as potential therapeutic targets are discussed.

Inflammageing in the cardiovascular system: mechanisms, emerging targets, and novel therapeutic strategies

In the elderly population, pathological inflammation has been associated with ageing-associated diseases. The term 'inflammageing', which was used for the first time by Franceschi and co-workers in 2000, is associated with the chronic, low-grade, subclinical inflammatory processes coupled to biological ageing. The source of these inflammatory processes is debated. The senescence-associated secretory phenotype (SASP) has been proposed as the main origin of inflammageing. The SASP is characterised by the release of inflammatory cytokines, elevated activation of the NLRP3 inflammasome, altered regulation of acetylcholine (ACh) nicotinic receptors, and abnormal NAD+ metabolism. Therefore, SASP may be 'druggable' by small molecule therapeutics targeting those emerging molecular targets. It has been shown that inflammageing is a hallmark of various cardiovascular diseases, including atherosclerosis, hypertension, and adverse cardiac remodelling. Therefore, the pathomechanism involving SASP activation via the NLRP3 inflammasome; modulation of NLRP3 via α7 nicotinic ACh receptors; and modulation by senolytics targeting other proteins have gained a lot of interest within cardiovascular research and drug development communities. In this review, which offers a unique view from both clinical and preclinical target-based drug discovery perspectives, we have focused on cardiovascular inflammageing and its molecular mechanisms. We have outlined the mechanistic links between inflammageing, SASP, interleukin (IL)-1β, NLRP3 inflammasome, nicotinic ACh receptors, and molecular targets of senolytic drugs in the context of cardiovascular diseases. We have addressed the 'druggability' of NLRP3 and nicotinic α7 receptors by small molecules, as these proteins represent novel and exciting targets for therapeutic interventions targeting inflammageing in the cardiovascular system and beyond.

Role of pyroptosis in atherosclerosis and its therapeutic implications

Atherosclerosis is a significant cardiovascular burden and a leading cause of death worldwide, recognized as a chronic sterile inflammatory disease. Pyroptosis is a novel proinflammatory regulated cell death, characterized by cell swelling, plasma membrane bubbling, and robust release of proinflammatory cytokines (such as interleukin IL-1β and IL-18). Mounting studies have addressed the crucial contribution of pyroptosis to atherosclerosis and clarified the candidate therapeutic agents targeting pyroptosis for atherosclerosis. Herein, we review the initial characterization of pyroptosis, the detailed mechanisms of pyroptosis, current evidence about pyroptosis and atherosclerosis, and potential therapeutic strategies that target pyroptosis in the development of atherosclerosis.

Targeting the NLRP3 inflammasome as new therapeutic avenue for inflammatory bowel disease

The incidence and prevalence of inflammatory bowel disease (IBD) are increasing worldwide. Current approved medication for IBD treatment in the clinic mainly includes corticosteroids and neutralization antibodies to pro-inflammatory cytokines. However, drug resistance and severe side effect hinder long-term efficacy of these agents. The NOD-like receptor family pyrin domain containing protein 3 (NLRP3) is exclusively expressed in several inflammatory and autoimmune diseases. Excessive expression, aberrant activation, polymorphism, and gain-of-function mutation of the NLRP3 inflammasome contribute to IBD pathogenesis. In this article, we summarize the regulatory factors to NLRP3, and review recently developed NLRP3 inhibitors and their preclinical and clinical applications in treating inflammatory and autoimmune diseases. We present our views on the therapeutic potential of NLRP3 inhibitors as emerging therapeutic avenue for IBD.

Effects of Tranilast on Inflammasome and Macrophage Phenotype in a Mouse Model of Myocardial Infarction

Acute myocardial infarction (AMI) has been a devastating actuality and accounts for half of cardiovascular emergency department visits. Nucleotide oligomerization domain, leucine-rich repeat, and pyrin domain-containing protein 3 (NLRP3) inflammasome participates in the mediation of myocardial inflammation during AMI. Therefore, this study aimed to reveal the therapeutic function of tranilast, an agent targeting NLRP3, for AMI. AMI mouse model was first established by transient myocardial ischemia. Western blot and quantitative reverse transcription polymerase chain reaction assay were performed to estimate the expression levels of related genes. Flow cytometry was used to analyze the macrophage types, and the therapeutic effects of tranilast were estimated by echocardiographic analysis and Masson's trichrome stain. We demonstrated that AMI induced the activation of NLRP3 inflammasome in the heart tissues of mice with AMI. Tranilast decreased the expression of interleukin-1β and cleaved caspase-1 in bone marrow-derived macrophages and thus re-educated M1-macrophages toward the M2-phenotype both in vitro and in vivo. Tranilast inhibited the activation in the heart tissues of AMI mice and thus improved cardiac functional recovery in the AMI mouse model. In conclusion, we revealed that tranilast ameliorated myocardial infarction by inhibiting NLRP3 inflammasome and re-educating macrophage phenotype in this study.

NLRP3 Inflammasome Inhibitors in Cardiovascular Diseases

Virtually all types of cardiovascular diseases are associated with pathological activation of the innate immune system. The NACHT, leucine-rich repeat (LRR), and pyrin domain (PYD)-containing protein 3 (NLRP3) inflammasome is a protein complex that functions as a platform for rapid induction of the inflammatory response to infection or sterile injury. NLRP3 is an intracellular sensor that is sensitive to danger signals, such as ischemia and extracellular or intracellular alarmins during tissue injury. The NLRP3 inflammasome is regulated by the presence of damage-associated molecular patterns and initiates or amplifies inflammatory response through the production of interleukin-1β (IL-1β) and/or IL-18. NLRP3 activation regulates cell survival through the activity of caspase-1 and gasdermin-D. The development of NLRP3 inflammasome inhibitors has opened the possibility to targeting the deleterious effects of NLRP3. Here, we examine the scientific evidence supporting a role for NLRP3 and the effects of inhibitors in cardiovascular diseases.

Regulation of the NLRP3 Inflammasome by Post-Translational Modifications and Small Molecules

Inflammation is a host protection mechanism that eliminates invasive pathogens from the body. However, chronic inflammation, which occurs repeatedly and continuously over a long period, can directly damage tissues and cause various inflammatory and autoimmune diseases. Pattern recognition receptors (PRRs) respond to exogenous infectious agents called pathogen-associated molecular patterns and endogenous danger signals called danger-associated molecular patterns. Among PRRs, recent advancements in studies of the NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome have established its significant contribution to the pathology of various inflammatory diseases, including metabolic disorders, immune diseases, cardiovascular diseases, and cancer. The regulation of NLRP3 activation is now considered to be important for the development of potential therapeutic strategies. To this end, there is a need to elucidate the regulatory mechanism of NLRP3 inflammasome activation by multiple signaling pathways, post-translational modifications, and cellular organelles. In this review, we discuss the intracellular signaling events, post-translational modifications, small molecules, and phytochemicals participating in the regulation of NLRP3 inflammasome activation. Understanding how intracellular events and small molecule inhibitors regulate NLRP3 inflammasome activation will provide crucial information for elucidating the associated host defense mechanism and the development of efficient therapeutic strategies for chronic diseases.

The Role of miRNA-146a and Proinflammatory Cytokines in Carotid Atherosclerosis

The aim of this study was to investigate the expression and significance of miRNA-146a in peripheral blood of patients with carotid atherosclerosis (CAS). Patients with CAS were selected as the stenosis (CAS) group (n = 180). According to the degree of stenosis, they were divided into the mild stenosis group (MS group, n = 64), moderate stenosis group (M group, n = 62 cases), and severe stenosis group (SS group, n = 54). According to the plaque type, patients were divided into a stable plaque group (SP group, n = 96) and a vulnerable plaque group (VP group, n = 84). Patients without CAS represented the normal group (n = 90). The expression levels of miRNA-146a as well as IL-6 and TNF-α in peripheral blood were detected by RT-PCR and ELISA, respectively. The expression levels of miRNA-146a, IL-6, and TNF-α in the CAS group were higher than those in the normal group and positively correlated with the degree of stenosis and plaque vulnerability. The expression levels of miRNA-146a, IL-6, and TNF-α in the stable plaque group were lower than those in the vulnerable plaque group. The area under the curve of miRNA-146a predicting the vulnerability of plaques was significant at 0.641. The expression level of miRNA-146a in the CAS group was positively correlated with IL-6 and TNF-α levels. Our results indicate that miRNA-146a may participate in the occurrence and development of CAS by regulating the expression of IL-6 and TNF-α, which may be potential biomarkers of CAS.

Recent efforts in drug discovery on vascular inflammation and consequent atherosclerosis

Introduction: Preservation of vascular endothelium integrity and maintenance of its full functionality are fundamental aspects in order to avoid both cardiovascular and non-cardiovascular diseases.Areas covered: Although a massive endothelial disruption is a rare condition, caused by acute and uncontrolled inflammatory responses (e.g. the cytokine storm induced by SARS-CoV-2 infection), more frequently the vascular tree is the first target of slowly progressive inflammatory processes which affect the integrity of endothelium and its 'barrier' function, supporting the onset of atherosclerotic plaque and spreading inflammation. This endothelial dysfunction leads to decrease NO biosynthesis, impaired regulation of vascular tone, and increased platelet aggregation. Such chronic subclinic inflammation leads to macrophage infiltration in atherosclerotic lesions. Therefore, many efforts should be addressed to find useful approaches to preserve vascular endothelium from inflammation. In this review, the authors have evaluated the most recent strategies to counteract this pathological condition.Expert opinion: The therapeutic and nutraceutical approaches represent useful tools to treat or prevent different phases of vascular inflammation. In particular, the pharmacological approach should be used in advanced phases characterized by clinical signs of vascular disease, whilst the nutraceutical approach may represent a promising preventive strategy to preserve the integrity of the endothelial tissue.

Inflammasome activation in acute lung injury

Inflammasomes are multiprotein complexes tasked with sensing endogenous or exogenous inflammatory signals and integrating this signal into a downstream response. Inflammasome activation has been implicated in a variety of pulmonary diseases, including pulmonary hypertension, bacterial pneumonia, COPD, and asthma. Of increasing interest is the contribution of inflammasome activation in the context of acute lung injury/acute respiratory distress syndrome (ALI/ARDS). Inflammasome activation in both the lung parenchyma and resident immune cells generates intereukin-1β (IL-1β) and IL-18, both of which drive the cascade of lung inflammation forward. Blockade of these responses has been shown to be beneficial in animal models and is a focus of translational research in the field. In this review, we will discuss the assembly and regulation of inflammasomes during lung inflammation, highlighting therapeutically viable effector steps. We will examine the importance of IL-1β and IL-18, two key products of inflammasome activation, in ALI, as well as the contribution of the pulmonary endothelial cell to this process. Finally, we will explore translational research moving toward anti-inflammasome therapies for ALI/ARDS and speculate toward future directions for the field.

Clematichinenoside AR Alleviates Foam Cell Formation and the Inflammatory Response in Ox-LDL-Induced RAW264.7 Cells by Activating Autophagy

Foam cell formation and inflammation in macrophages contribute to the development of atherosclerosis (AS). Clematichinenoside AR (AR) is a major active ingredient extracted from the traditional Chinese herb Clematis chinensis and has potent pharmacological effects on various diseases, including AS. However, little is known about the exact role and mechanism of AR in AS. RAW264.7 macrophages were exposed to oxidized low-density lipoprotein (ox-LDL) to induce AS in vitro. Cell viability was assessed by the CCK-8 assay. Foam cell formation was detected by Oil Red staining. Cholesterol levels were determined by corresponding commercial kits. The expression of inflammatory cytokines was detected by ELISA. Western blot and immunofluorescence assays were employed to detect the expression of corresponding genes. The results indicated that AR treatment inhibited the formation of foam cells and cholesterol accumulation but promoted cholesterol efflux by upregulating ABCA1/ABCG1 in ox-LDL-induced RAW264.7 macrophages. In addition, AR decreased the production of inflammatory cytokines by blunting the activation of the NLRP3 inflammasome and inducing autophagy. However, these effects of AR were weakened by the autophagy inhibitor bafilomycin A1 but were similar to those produced by the autophagy activator rapamycin. Collectively, our study provides novel insights into the beneficial effects of AR on promoting cholesterol efflux as well as inhibiting foam cell formation and inflammation by regulating autophagy, thus identifying AR as a promising therapeutic agent for the treatment of AS.

NLRP3 inflammasome in endothelial dysfunction

Inflammasomes are a class of cytosolic protein complexes. They act as cytosolic innate immune signal receptors to sense pathogens and initiate inflammatory responses under physiological and pathological conditions. The NLR-family pyrin domain-containing protein 3 (NLRP3) inflammasome is the most characteristic multimeric protein complex. Its activation triggers the cleavage of pro-interleukin (IL)-1β and pro-IL-18, which are mediated by caspase-1, and secretes mature forms of these mediators from cells to promote the further inflammatory process and oxidative stress. Simultaneously, cells undergo pro-inflammatory programmed cell death, termed pyroptosis. The danger signals for activating NLRP3 inflammasome are very extensive, especially reactive oxygen species (ROS), which act as an intermediate trigger to activate NLRP3 inflammasome, exacerbating subsequent inflammatory cascades and cell damage. Vascular endothelium at the site of inflammation is actively involved in the regulation of inflammation progression with important implications for cardiovascular homeostasis as a dynamically adaptable interface. Endothelial dysfunction is a hallmark and predictor for cardiovascular ailments or adverse cardiovascular events, such as coronary artery disease, diabetes mellitus, hypertension, and hypercholesterolemia. The loss of proper endothelial function may lead to tissue swelling, chronic inflammation, and the formation of thrombi. As such, elimination of endothelial cell inflammation or activation is of clinical relevance. In this review, we provided a comprehensive perspective on the pivotal role of NLRP3 inflammasome activation in aggravating oxidative stress and endothelial dysfunction and the possible underlying mechanisms. Furthermore, we highlighted the contribution of noncoding RNAs to NLRP3 inflammasome activation-associated endothelial dysfunction, and outlined potential clinical drugs targeting NLRP3 inflammasome involved in endothelial dysfunction. Collectively, this summary provides recent developments and perspectives on how NLRP3 inflammasome interferes with endothelial dysfunction and the potential research value of NLRP3 inflammasome as a potential mediator of endothelial dysfunction.

Novel Role for Tranilast in Regulating NLRP3 Ubiquitination, Vascular Inflammation, and Atherosclerosis

Background

Aberrant activation of the NLRP3 (nucleotide‐binding oligomerization domain, leucine‐rich repeat–containing receptor family pyrin domain‐containing 3) inflammasome is thought to play a causative role in atherosclerosis. NLRP3 is kept in an inactive ubiquitinated state to avoid unwanted NLRP3 inflammasome activation. This study aimed to test the hypothesis that pharmacologic manipulating of NLRP3 ubiquitination blunts the assembly and activation of the NLRP3 inflammasome and protects against vascular inflammation and atherosclerosis. Since genetic studies yielded mixed results about the role for this inflammasome in atherosclerosis in low‐density lipoprotein receptor– or apolipoprotein E–deficient mice, this study attempted to clarify the discrepancy with the pharmacologic approach using both models.

Methods and Results

We provided the first evidence demonstrating that tranilast facilitates NLRP3 ubiquitination. We showed that tranilast restricted NLRP3 oligomerization and inhibited NLRP3 inflammasome assembly. Tranilast markedly suppressed NLRP3 inflammasome activation in low‐density lipoprotein receptor– and apolipoprotein E–deficient macrophages. Through reconstitution of the NLRP3 inflammasome in human embryonic kidney 293T cells, we found that tranilast directly limited NLRP3 inflammasome activation. By adopting different regimens for tranilast treatment of low‐density lipoprotein receptor– and apolipoprotein E–deficient mice, we demonstrated that tranilast blunted the initiation and progression of atherosclerosis. Mice receiving tranilast displayed a significant reduction in atherosclerotic lesion size, concomitant with a pronounced decline in macrophage content and expression of inflammatory molecules in the plaques compared with the control group. Moreover, tranilast treatment of mice substantially hindered the expression and activation of the NLRP3 inflammasome in the atherosclerotic lesions.

Conclusions

Tranilast potently enhances NLRP3 ubiquitination, blunts the assembly and activation of the NLRP3 inflammasome, and ameliorates vascular inflammation and atherosclerosis in both low‐density lipoprotein receptor– and apolipoprotein E–deficient mice.