Therapeutic potential of the target on NLRP3 inflammasome in multiple sclerosis

Unmasking the NLRP3 inflammasome in dendritic cells as a potential therapeutic target for autoimmunity, cancer, and infectious conditions

Proper and functional immune response requires a complex interaction between innate and adaptive immune cells, which dendritic cells (DCs) are the primary actors in this coordination as professional antigen-presenting cells. DCs are armed with numerous pattern recognition receptors (PRRs) such as nucleotide-binding and oligomerization domain-like receptors (NLRs) like NLRP3, which influence the development of their activation state upon sensation of ligands. NLRP3 is a crucial component of the immune system for protection against tumors and infectious agents, because its activation leads to the assembly of inflammasomes that cause the formation of active caspase-1 and stimulate the maturation and release of proinflammatory cytokines. But, when NLRP3 becomes overactivated, it plays a pathogenic role in the progression of several autoimmune disorders. So, NLRP3 activation is strictly regulated by diverse signaling pathways that are mentioned in detail in this review. Furthermore, the role of NLRP3 in all of the diverse immune cells' subsets is briefly mentioned in this study because NLRP3 plays a pivotal role in modulating other immune cells which are accompanied by DCs' responses and subsequently influence differentiation of T cells to diverse T helper subsets and even impact on cytotoxic CD8+ T cells' responses. This review sheds light on the functional and therapeutic role of NLRP3 in DCs and its contribution to the occurrence and progression of autoimmune disorders, prevention of diverse tumors' development, and recognition and annihilation of various infectious agents. Furthermore, we highlight NLRP3 targeting potential for improving DC-based immunotherapeutic approaches, to be used for the benefit of patients suffering from these disorders.

Augmented microglial endoplasmic reticulum-mitochondria contacts mediate depression-like behavior in mice induced by chronic social defeat stress

Extracellular ATP (eATP) signaling through the P2X7 receptor pathway is widely believed to trigger NLRP3 inflammasome assembly in microglia, potentially contributing to depression. However, the cellular stress responses of microglia to both eATP and stress itself remain largely unexplored. Mitochondria-associated membranes (MAMs) is a platform facilitating calcium transport between the endoplasmic reticulum (ER) and mitochondria, regulating ER stress responses and mitochondrial homeostasis. This study aims to investigate how MAMs influence microglial reaction and their involvement in the development of depression-like symptoms in response to chronic social defeat stress (CSDS). CSDS induced ER stress, MAMs' modifications, mitochondrial damage, and the formation of the IP3R3-GRP75-VDAC1 complex at the ER-mitochondria interface in hippocampal microglia, all concomitant with depression-like behaviors. Additionally, exposing microglia to eATP to mimic CSDS conditions resulted in analogous outcomes. Furthermore, knocking down GRP75 in BV2 cells impeded ER-mitochondria contact, calcium transfer, ER stress, mitochondrial damage, mitochondrial superoxide production, and NLRP3 inflammasome aggregation induced by eATP. In addition, reduced GRP75 expression in microglia of Cx3cr1CreER/+Hspa9f/+ mice lead to reduce depressive behaviors, decreased NLRP3 inflammasome aggregation, and fewer ER-mitochondria contacts in hippocampal microglia during CSDS. Here, we show the role of MAMs, particularly the formation of a tripartite complex involving IP3R3, GRP75, and VDAC1 within MAMs, in facilitating communication between the ER and mitochondria in microglia, thereby contributing to the development of depression-like phenotypes in male mice.

NLRP3 inflammasome and its role in autoimmune diseases: A promising therapeutic target

The NOD-like receptor protein 3 (NLRP3) inflammasome is a protein complex that regulates innate immune responses by activating caspase-1 and the inflammatory cytokines IL-1β and IL-18. Numerous studies have highlighted its crucial role in the pathogenesis and development of inflammatory bowel disease, rheumatoid arthritis, systemic lupus erythematosus, autoimmune thyroid diseases, and other autoimmune diseases. Therefore, investigating the underlying mechanisms of NLRP3 in disease and targeted drug therapies holds clinical significance. This review summarizes the structure, assembly, and activation mechanisms of the NLRP3 inflammasome, focusing on its role and involvement in various autoimmune diseases. This review also identifies studies where the involvement of the NLRP3 inflammasome in the disease mechanism within the same disease appears contradictory, as well as differences in NLRP3-related gene polymorphisms among different ethnic groups. Additionally, the latest therapeutic advances in targeting the NLRP3 inflammasome for autoimmune diseases are outlined, and novel clinical perspectives are discussed. Conclusively, this review provides a consolidated source of information on the NLRP3 inflammasome and may guide future research efforts that have the potential to positively impact patient outcomes.

Pyroptosis: a new insight into intestinal inflammation and cancer

Pyroptosis is an innate immune response triggered by the activation of inflammasomes by various influencing factors, characterized by cell destruction. It impacts the immune system and cancer immunotherapy. In recent years, the roles of pyroptosis and inflammasomes in intestinal inflammation and cancer have been continuously confirmed. This article reviews the latest progress in pyroptosis mechanisms, new discoveries of inflammasomes, mutual regulation between inflammasomes, and their applications in intestinal diseases. Additionally, potential synergistic treatment mechanisms of intestinal diseases with pyroptosis are summarized, and challenges and future directions are discussed, providing new ideas for pyroptosis therapy.

Intestinal microbiota regulates the gut-thyroid axis: the new dawn of improving Hashimoto thyroiditis

Intestinal microbiota plays an indispensable role in the host's innate immune system, which may be related to the occurrence of many autoimmune diseases. Hashimoto thyroiditis (HT) is one of the most common autoimmune diseases, and there is plenty of evidence indicating that HT may be related to genetics and environmental triggers, but the specific mechanism has not been proven clearly. Significantly, the composition and abundance of intestinal microbiota in patients with HT have an obvious difference. This phenomenon led us to think about whether intestinal microbiota can affect the progress of HT through some mechanisms. By summarizing the potential mechanism of intestinal microflora in regulating Hashimoto thyroiditis, this article explores the possibility of improving HT by regulating intestinal microbiota and summarizes relevant biomarkers as therapeutic targets, which provide new ideas for the clinical diagnosis and treatment of Hashimoto thyroiditis.

Role of fenofibrate in multiple sclerosis

Multiple sclerosis (MS) is the most frequent inflammatory and demyelinating disease of the central nervous system (CNS). The underlying pathophysiology of MS is the destruction of myelin sheath by immune cells. The formation of myelin plaques, inflammation, and injury of neuronal myelin sheath characterizes its neuropathology. MS plaques are multiple focal regions of demyelination disseminated in the brain's white matter, spinal cords, deep grey matter, and cerebral cortex. Fenofibrate is a peroxisome proliferative activated receptor alpha (PPAR-α) that attenuates the inflammatory reactions in MS. Fenofibrate inhibits differentiation of Th17 by inhibiting the expression of pro-inflammatory signaling. According to these findings, this review intended to illuminate the mechanistic immunoinflammatory role of fenofibrate in mitigating MS neuropathology. In conclusion, fenofibrate can attenuate MS neuropathology by modulating different pathways, including oxidative stress, autophagy, mitochondrial dysfunction, inflammatory-signaling pathways, and neuroinflammation.

Drugging the NLRP3 inflammasome: from signalling mechanisms to therapeutic targets

Diseases associated with chronic inflammation constitute a major health burden across the world. As central instigators of the inflammatory response to infection and tissue damage, inflammasomes - and the NACHT, LRR and PYD domain-containing protein 3 (NLRP3) inflammasome in particular - have emerged as key regulators in diverse rheumatic, metabolic and neurodegenerative diseases. Similarly to other inflammasome sensors, NLRP3 assembles a cytosolic innate immune complex that activates the cysteine protease caspase-1, which in turn cleaves gasdermin D (GSDMD) to induce pyroptosis, a regulated mode of lytic cell death. Pyroptosis is highly inflammatory, partly because of the concomitant extracellular release of the inflammasome-dependent cytokines IL-1β and IL-18 along with a myriad of additional danger signals and intracellular antigens. Here, we discuss how NLRP3 and downstream inflammasome effectors such as GSDMD, apoptosis-associated speck-like protein containing a CARD (ASC) and nerve injury-induced protein 1 (NINJ1) have gained significant traction as therapeutic targets. We highlight the recent progress in developing small-molecule and biologic inhibitors that are advancing into the clinic and serving to harness the broad therapeutic potential of modulating the NLRP3 inflammasome.

Tonabersat Significantly Reduces Disease Progression in an Experimental Mouse Model of Multiple Sclerosis

Multiple sclerosis (MS) is a neurodegenerative disease marked by chronic neuroinflammation thought to be mediated by the inflammasome pathway. Connexin 43 (Cx43) hemichannels contribute to the activation of the inflammasome through the release of adenosine triphosphate (ATP) inflammasome activation signals. The objective of the study was to evaluate if the Cx43 hemichannel blocker, tonabersat, is effective in modulating the inflammatory response and reducing disability in the myelin oligodendrocyte glycoprotein 35-55-induced experimental autoimmune encephalomyelitis (MOG35-55 EAE) model of MS. Here, we show that the Cx43 hemichannel blocking drug, tonabersat, significantly reduced expression of neuroinflammatory markers for microglial activation (ionized calcium-binding adapter molecule 1 (Iba1)) and astrogliosis (glial fibrillary acidic protein (GFAP)) while preserving myelin basic protein (MBP) expression levels in the corpus callosum, motor cortex, and striatum regions of the brain in MOG35-55 EAE mice. Reduced NOD-like receptor protein 3 (NLRP3) inflammasome complex assembly and Caspase-1 activation confirmed the drug's mode of action. MOG35-55 EAE mice showed clinical signs of MS, but MOG35-55 EAE mice treated with tonabersat retained behavior closer to normal. These data suggest that clinical trial phase IIb-ready tonabersat may merit further investigation as a promising candidate for MS treatment.

The pathogenesis and potential therapeutic targets in sepsis

Sepsis is defined as "a life-threatening organ dysfunction caused by dysregulated host systemic inflammatory and immune response to infection." At present, sepsis continues to pose a grave healthcare concern worldwide. Despite the use of supportive measures in treating traditional sepsis, such as intravenous fluids, vasoactive substances, and oxygen plus antibiotics to eradicate harmful pathogens, there is an ongoing increase in both the morbidity and mortality associated with sepsis during clinical interventions. Therefore, it is urgent to design specific pharmacologic agents for the treatment of sepsis and convert them into a novel targeted treatment strategy. Herein, we provide an overview of the molecular mechanisms that may be involved in sepsis, such as the inflammatory response, immune dysfunction, complement deactivation, mitochondrial damage, and endoplasmic reticulum stress. Additionally, we highlight important targets involved in sepsis-related regulatory mechanisms, including GSDMD, HMGB1, STING, and SQSTM1, among others. We summarize the latest advancements in potential therapeutic drugs that specifically target these signaling pathways and paramount targets, covering both preclinical studies and clinical trials. In addition, this review provides a detailed description of the crosstalk and function between signaling pathways and vital targets, which provides more opportunities for the clinical development of new treatments for sepsis.

Inflammasomes cross-talk with lymphocytes to connect the innate and adaptive immune response

BACKGROUND

Innate and adaptive immunity are two different parts of the immune system that have different characteristics and work together to provide immune protection. Inflammasomes are a major part of the innate immune system that are expressed widely in myeloid cells and are responsible for inflammatory responses. Recent studies have shown that inflammasomes are also expressed and activated in lymphocytes, especially in T and B cells, to regulate the adaptive immune response. Activation of inflammasomes is also under the control of lymphocytes. Therefore, we propose that inflammasomes act as a bridge and they provide crosstalk between the innate and adaptive immune systems to obtain a fine balance in immune responses.

AIM OF REVIEW

This review systematially summarizes the interaction between inflammasomes and lymphocytes and describes the crosstalk between the innate and adaptive immune systems induced by inflammasomes, with the aim of providing new directions and important areas for further research.

KEY SCIENTIFIC CONCEPTS OF REVIEW

When considering the novel function of inflammasomes in various lymphocytes, attention should be given to the activity of specific inflammasomes in studies of lymphocyte function. Moreover, research on the function of various inflammasomes in lymphocytes will help advance knowledge on the mechanisms and treatment of various diseases, including autoimmune diseases and tumors. In addition, when studying inflammatory responses, inflammasomes in both lymphocytes and myeloid cells need to be considered.

Inhibited Expression of NLRP12 Promotes the Development of Triple-Negative Breast Cancer by Activating the NF-κB Pathway

NLRP12 can affect the progression of different diseases, including hepatocellular carcinoma. However, no report on triple-negative breast cancer (TNBC) has been found. Thus, this study aimed to explore the role of NLRP12 in TNBC. In our study, immunohistochemistry, real-time quantitative PCR (qPCR), and Western blot assays were used to evaluate NLRP12 expression in TNBC tissues and cells. Then, NLRP12 lentivirus was constructed and infected into MDA-MB-231 and MDA-MB-157 cells with or without PTD-p65-P1 treatment. Next, cells were collected for cell function detection using the following procedures: colony formation assay for proliferation, Transwell for migration and invasion, and Western blot for NF-κB and MAPK pathway-associated proteins. Finally, a xenograft mouse model was applied; the tumor volume and weight were determined, and NLRP12, p-IκBb-α, and p-IκBb-α expressions were evaluated using qPCR and Western blot. Results indicated that NLRP12 was lowly expressed in TNBC tissues and cells. The inhibition of NLRP12 could induce the proliferation, migration, and invasion of TNBC cells, which also could be reversed by inhibiting the NF-κB pathway (PTD-p65-P1). Moreover, silencing of NLRP12 could upregulate p-IκBb-α, while IκBb-α, p-ERK, ERK, p-p38, p38, p-JNK, and JNK expressions remained unchanged, thereby indicating that only the NF-κB pathway could be activated by NLRP12 silencing. Furthermore, the xenograft mouse model confirmed the abovementioned findings. Therefore, the low expression of NLRP12 promoted the proliferation, migration, and invasion in TNBC cells by activating the NF-κB pathway. This study might provide insights into TNBC therapy.

Estrogen plays an important role by influencing the NLRP3 inflammasome

The nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome is an important part of the natural immune system that plays an important role in many diseases. Estrogen is a sex hormone that plays an important role in controlling reproduction and regulates many physiological and pathological processes. Recent studies have indicated that estrogen is associated with disease progression. Estrogen can ameliorate some diseases (e. g, sepsis, mood disturbances, cerebral ischemia, some hepatopathy, Parkinson's disease, amyotrophic lateral sclerosis, inflammatory bowel disease, spinal cord injury, multiple sclerosis, myocardial ischemia/reperfusion injury, osteoarthritis, and renal fibrosis) by inhibiting the NLRP3 inflammasome. Estrogen can also promote the development of diseases (e.g., ovarian endometriosis, dry eye disease, and systemic lupus erythematosus) by upregulating the NLRP3 inflammasome. In addition, estrogen has a dual effect on the development of cancers and asthma. However, the mechanism of these effects is not summarized. This article reviewed the progress in understanding the effects of estrogen on the NLRP3 inflammasome and its mechanisms in recent years to provide a theoretical basis for an in-depth study.

Pathogenic Role of Fibrinogen in the Neuropathology of Multiple Sclerosis: A Tale of Sorrows and Fears

Multiple sclerosis (MS) is an autoimmune demyelinating neurodegenerative disease of the central nervous system (CNS) due to injury of the myelin sheath by immune cells. The clotting factor fibrinogen is involved in the pathogenesis of MS by triggering microglia and the progress of neuroinflammation. Fibrinogen level is correlated with MS severity; consequently, inhibition of the fibrinogen cascade may reduce MS neuropathology. Thus, this review aimed to clarify the potential role of fibrinogen in the pathogenesis of MS and how targeting of fibrinogen affects MS neuropathology. Accumulation of fibrinogen in the CNS may occur independently or due to disruption of blood-brain barrier (BBB) integrity in MS. Fibrinogen acts as transduction and increases microglia activation which induces the progression of inflammation, oxidative stress, and neuronal injury. Besides, brain fibrinogen impairs the remyelination process by inhibiting the differentiation of oligodendrocyte precursor cells. These findings proposed that fibrinogen is associated with MS neuropathology through interruption of BBB integrity, induction of neuroinflammation, and demyelination with inhibition of the remyelination process by suppressing oligodendrocytes. Therefore, targeting of fibrinogen and/or CD11b/CD18 receptors by metformin and statins might decrease MS neuropathology. In conclusion, inhibiting the expression of CD11b/CD18 receptors by metformin and statins may decrease the pro-inflammatory effect of fibrinogen on microglia which is involved in the progression of MS.

NLRP3 inflammasome involves in the pathophysiology of sepsis-induced myocardial dysfunction by multiple mechanisms

Sepsis-induced myocardial dysfunction (SIMD) is one of the serious health-affecting problems worldwide. At present, the mechanisms of SIMD are still not clearly elucidated. The NOD-like receptor protein 3 (NLRP3) inflammasome has been assumed to be involved in the pathophysiology of SIMD by regulating multiple biological processes. NLRP3 inflammasome and its related signaling pathways might affect the regulation of inflammation, autophagy, apoptosis, and pyroptosis in SIMD. A few molecular specific inhibitors of NLRP3 inflammasome (e.g., Melatonin, Ulinastatin, Irisin, Nifuroxazide, and Ginsenoside Rg1, etc.) have been developed, which showed a promising anti-inflammatory effect in a cellular or animal model of SIMD. These experimental findings indicated that NLRP3 inflammasome could be a promising therapeutic target for SIMD treatment. However, the clinical translation of NLRP3 inhibitors for treating SIMD still requires robust in vivo and preclinical trials.

Integrated Analysis of Immune Infiltration and Hub Pyroptosis-Related Genes for Multiple Sclerosis

Purpose

Studies on overall immune infiltration and pyroptosis in patients with multiple sclerosis (MS) are limited. This study explored immune cell infiltration and pyroptosis in MS using bioinformatics and experimental validation.

Methods

The GSE131282 and GSE135511 microarray datasets including brain autopsy tissues from controls and MS patients were downloaded for bioinformatic analysis. The gene expression-based deconvolution method, CIBERSORT, was used to determine immune infiltration. Differentially expressed genes (DEGs) and functional enrichments were analyzed. We then extracted pyroptosis-related genes (PRGs) from the DEGs by using machine learning strategies. Their diagnostic ability for MS was evaluated in both the training set (GSE131282 dataset) and validation set (GSE135511 dataset). In addition, messenger RNA (mRNA) expression of PRGs was validated using quantitative real-time polymerase chain reaction (qRT-PCR) in cortical tissue from an experimental autoimmune encephalomyelitis (EAE) model of MS. Moreover, the functional enrichment pathways of each hub PRG were estimated. Finally, co-expressed competitive endogenous RNA (ceRNA) networks of PRGs in MS were constructed.

Results

Among the infiltrating cells, naive CD4+ T cells (P=0.006), resting NK cells (P=0.002), activated mast cells (P=0.022), and neutrophils (P=0.002) were significantly higher in patients with MS than in controls. The DEGs of MS were screened. Analysis of enrichment pathways showed that the pathways of transcriptional regulatory mechanisms and ion channels associating with pyroptosis. Four PRGs genes CASP4, PLCG1, CASP9 and NLRC4 were identified. They were validated in both the GSE135511 dataset and the EAE model by using qRT-PCR. CASP4 and NLRC4 were ultimately identified as stable hub PRGs for MS. Single-gene Gene Set Enrichment Analysis showed that they mainly participated in biosynthesis, metabolism, and organism resistance. ceRNA networks containing CASP4 and NLRC4 were constructed.

Conclusion

MS was associated with immune infiltration. CASP4 and NLRC4 were key biomarkers of pyroptosis in MS.

Cholesterol-autoxidation metabolites in host defense against infectious diseases

Cholesterol plays essential roles in biological processes, including cell membrane stability and myelin formation. Cholesterol can be metabolized to oxysterols by enzymatic or nonenzymatic ways. Nonenzymatic cholesterol metabolites, also called cholesterol-autoxidation metabolites, are formed dependent on the oxidation of reactive oxygen species (ROS) such as OH• or reactive nitrogen species, such as ONOO- . Cholesterol-autoxidation metabolites are abundantly produced in diseases such as inflammatory bowel disease and atherosclerosis, which are associated with oxidative stress. Recent studies have shown that cholesterol-autoxidation metabolites can further regulate the immune system. Here, we review the literature and summarize how cholesterol-autoxidation metabolites, such as 25-hydroxycholesterol (25-OHC), 7α/β-OHC, and 7-ketocholesterol, deal with the occurrence and development of infectious diseases through pattern recognition receptors, inflammasomes, ROS production, nuclear receptors, G-protein-coupled receptor 183, and lipid availability. In addition, we include the research regarding the roles of these metabolites in COVID-19 infection and discuss our viewpoints on the future research directions.

Application of pyroptosis in tumor research (Review)

As a potent clinical strategy, cancer therapy has sparked an academic boom over the past few years. Immune checkpoint inhibitors (ICIs) have been demonstrated to be highly successful. These achievements have progressed cancer treatment and have made an indelible mark on cancer. However, the inherent complexity of cancer means that only part of the population can benefit from this treatment. Pyroptosis is a new suicidal cellular mechanism that induces inflammation by releasing immunogenic cellular components. Inflammatory signaling cascades mediated by pyroptosis commonly inspire numerous cell lysis in immune diseases. Contrariwise, this consequence may be a promising target in cancer research. Therefore, the present study briefly described programmed cell death processes and their potential roles in cancer. Because of the rapid development of bioengineering in cancer, the present study also examined the associated scaffolding available for cancer, highlighting advances in tumor engineering approaches. Ultimately, an improved understanding of pyroptosis and tumor scaffolding might shed light on a combination that can be manipulated for therapeutic purposes.

Exploring the impact of ketogenic diet on multiple sclerosis: obesity, anxiety, depression, and the glutamate system

Background

Multiple sclerosis (MS) is a neurodegenerative disorder. Individuals with MS frequently present symptoms such as functional disability, obesity, and anxiety and depression. Axonal demyelination can be observed and implies alterations in mitochondrial activity and increased inflammation associated with disruptions in glutamate neurotransmitter activity. In this context, the ketogenic diet (KD), which promotes the production of ketone bodies in the blood [mainly β-hydroxybutyrate (βHB)], is a non-pharmacological therapeutic alternative that has shown promising results in peripheral obesity reduction and central inflammation reduction. However, the association of this type of diet with emotional symptoms through the modulation of glutamate activity in MS individuals remains unknown.

Aim

To provide an update on the topic and discuss the potential impact of KD on anxiety and depression through the modulation of glutamate activity in subjects with MS.

Discussion

The main findings suggest that the KD, as a source of ketone bodies in the blood, improves glutamate activity by reducing obesity, which is associated with insulin resistance and dyslipidemia, promoting central inflammation (particularly through an increase in interleukins IL-1β, IL-6, and IL-17). This improvement would imply a decrease in extrasynaptic glutamate activity, which has been linked to functional disability and the presence of emotional disorders such as anxiety and depression.

NLRP3: a new therapeutic target in alcoholic liver disease

The liver is in charge of a wide range of critical physiological processes and it plays an important role in activating the innate immune system which elicits the inflammatory events. Chronic ethanol exposure disrupts hepatic inflammatory mechanism and leads to the release of proinflammatory mediators such as chemokines, cytokines and activation of inflammasomes. The mechanism of liver fibrosis/cirrhosis involve activation of NLRP3 inflammasome, leading to the destruction of hepatocytes and subsequent metabolic dysregulation in humans. In addition, increasing evidence suggests that alcohol intake significantly modifies liver epigenetics, promoting the development of alcoholic liver disease (ALD). Epigenetic changes including histone modification, microRNA-induced genetic modulation, and DNA methylation are crucial in alcohol-evoked cell signaling that affects gene expression in the hepatic system. Though we are at the beginning stage without having the entire print of epigenetic signature, it is time to focus more on NLRP3 inflammasome and epigenetic modifications. Here we review the novel aspect of ALD pathology linking to inflammation and highlighting the role of epigenetic modification associated with NLRP3 inflammasome and how it could be a therapeutic target in ALD.

Altered Lnc-EGFR, SNHG1, and LincRNA-Cox2 Profiles in Patients with Relapsing-Remitting Multiple Sclerosis: Impact on Disease Activity and Progression

Relapsing-remitting multiple sclerosis (RRMS) is the most prevalent MS subtype. Ample evidence has indicated that long noncoding RNAs (lncRNAs) are crucial players in autoimmune and inflammatory disorders. This study investigated the expression of lnc-EGFR, SNHG1, and lincRNA-Cox2 in RRMS patients during active relapses and in remission. Additionally, the expression of FOXP3, a master transcription factor for regulatory T cells, and NLRP3-inflammasome-related genes were determined. Relationships between these parameters and MS activity and annualized relapse rate (ARR) were also evaluated. The study included 100 Egyptian participants: 70 RRMS patients (35 during relapse and 35 in remission) and 30 healthy controls. RRMS patients showed significant downregulation of lnc-EGFR and FOXP3 and dramatic upregulation of SNHG1, lincRNA-Cox2, NLRP3, ASC, and caspase-1 compared to controls. Lower serum TGF-β1 and elevated IL-1β levels were observed in RRMS patients. Notably, patients during relapses displayed more significant alterations than those in remission. Lnc-EGFR was positively correlated with FOXP3 and TGF-β1 and negatively correlated with ARR, SNHG1, lincRNA-Cox2, and NLRP3 inflammasome components. Meanwhile, SNHG1 and lincRNA-Cox2 were positively correlated with ARR, NLRP3, ASC, caspase-1, and IL-1β. Excellent diagnostic performance for lnc-EGFR, FOXP3, and TGF-β1 was demonstrated, while all biomarkers exhibited strong prognostic potential for predicting relapses. Finally, the differential expression of lnc-EGFR, SNHG1, and lincRNA-Cox2 in RRMS patients, especially during relapses, suggests their involvement in RRMS pathogenesis and activity. Correlation between their expression and ARR implies relationships to disease progression. Our findings also highlight their promising roles as biomarkers for RRMS.

Atranorin inhibits NLRP3 inflammasome activation by targeting ASC and protects NLRP3 inflammasome-driven diseases

Aberrant NLRP3 activation has been implicated in the pathogenesis of numerous inflammation-associated diseases. However, no small molecular inhibitor that directly targets NLRP3 inflammasome has been approved so far. In this study, we show that Atranorin (C₁₉H₁₈O₈), the secondary metabolites of lichen family, effectively prevents NLRP3 inflammasome activation in macrophages and dendritic cells. Mechanistically, Atranorin inhibits NLRP3 activation induced cytokine secretion and cell pyroptosis through binding to ASC protein directly and therefore restraining ASC oligomerization. The pharmacological effect of Atranorin is evaluated in NLRP3 inflammasome-driven disease models. Atranorin lowers serum IL-1β and IL-18 levels in LPS induced mice acute inflammation model. Also, Atranorin protects against MSU crystal induced mice gouty arthritis model and lowers ankle IL-1β level. Moreover, Atranorin ameliorates intestinal inflammation and epithelial barrier dysfunction in DSS induced mice ulcerative colitis and inhibits NLRP3 inflammasome activation in colon. Altogether, our study identifies Atranorin as a novel NLRP3 inhibitor that targets ASC protein and highlights the potential therapeutic effects of Atranorin in NLRP3 inflammasome-driven diseases including acute inflammation, gouty arthritis and ulcerative colitis.

Sennoside A is a novel inhibitor targeting caspase-1

The assembly of inflammasomes drives caspase-1 activation, which further promotes proinflammatory cytokine secretion and downstream pyroptosis. The discovery of novel caspase-1 inhibitors is pivotal to developing new therapeutic means for inflammasome-involved diseases. In our present study, sennoside A (Sen A), a popular ingredient in multiple weight-loss medicines and dietary supplements, is found to potently inhibit the enzymatic activity of caspase-1 in vitro. Sen A considerably decreased IL-1β production in macrophages stimulated by LPS plus ATP, nigericin or MSU as well as poly(dA:dT) transfection, and remedied ROS-involved pyroptosis via caspase-1 inhibition. Mechanistically, Sen A not only suppressed the assembly of both NLRP3 and AIM2 inflammasome but also affected the priming process of NLRP3 inflammasome by blocking NF-κB signaling. Sen A significantly ameliorated the pathophysiological effect in LPS-, MSU- and carrageenan-challenged rodent models by suppressing inflammasome activation. Furthermore, P2X7 was indispensable for Sen A inhibiting NLRP3 inflammasome since it failed to further decrease IL-1β and IL-18 production in LPS plus ATP-stimulated BMDMs that were transfected with P2X7 siRNA. Sen A also restrained the large pore-forming functionalities of the P2X7R as verified by the YO-PRO-1 uptake assay. Taken together, Sen A inactivates caspase-1 to inhibit NLRP3 and AIM2 inflammasome-involved inflammation in a P2X7-dependent manner, making it an attractive candidate as a caspase-1 small-molecular inhibitor.

Does Pyroptosis Play a Role in Inflammasome-Related Disorders?

Inflammasomes are multiprotein complexes orchestrating intracellular recognition of endogenous and exogenous stimuli, cellular homeostasis, and cell death. Upon sensing of certain stimuli, inflammasomes typically activate inflammatory caspases that promote the production and release of the proinflammatory cytokines IL-1β, IL-1α, and IL-18 and induce a type of inflammatory cell death known as “pyroptosis”. Pyroptosis is an important form of regulated cell death executed by gasdermin proteins, which is largely different from apoptosis and necrosis. Recently, several signaling pathways driving pyroptotic cell death, including canonical and noncanonical inflammasome activation, as well as caspase-3-dependent pathways, have been reported. While much evidence exists that pyroptosis is involved in the development of several inflammatory diseases, its contribution to inflammasome-related disorders (IRDs) has not been fully clarified. This article reviews molecular mechanisms leading to pyroptosis, and attempts to provide evidence for its possible role in inflammasome-related disorders, including NLR pyrin domain containing 3 (NLRP3) inflammasome disease, NLR containing a caspase recruitment domain 4 (NLRC4) inflammasome disease, and pyrin inflammasome disease. Although the specific mechanism needs further investigations, these studies have uncovered the role of pyroptosis in inflammasome-related disorders and may open new avenues for future therapeutic interventions.

Protective effect of ginsenoside Rh2 against Toxoplasma gondii infection-induced neuronal injury through binding TgCDPK1 and NLRP3 to inhibit microglial NLRP3 inflammasome signaling pathway

BACKGROUND

Toxoplasma gondii (T. gondii) is a neurotropic obligate intracellular parasite that can activate microglial and promote neuronal apoptosis, leading to central nervous system diseases. The NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome signaling complex plays a key role in inducing neuroinflammation. Our previous studies have found that ginsenoside Rh2 (GRh2) inhibits T. gondii infection-induced microglial activation and neuroinflammation by downregulating the Toll-like receptor 4/nuclear factor-kappa B signaling pathway. However, whether GRh2 reduces T. gondii infection-induced neuronal injury through actions on microglial NLRP3 inflammasome signaling has not yet been clarified.

METHODS

In this study, we employed T. gondii RH strain to establish in vitro and in vivo infection models in BV2 microglia cell line and BALB/c mice. Molecular docking, localized surface plasmon resonance assay, quantitative competitive-PCR, ELISA, western blotting, flow cytometric analysis, and immunofluorescence were performed.

RESULTS

Our results showed that GRh2 alleviated neuropathological damage and neuronal apoptosis in cortical tissue of T. gondii-infected mice. GRh2 and CY-09 (an inhibitor of NLRP3) exhibited potent anti-T. gondii effects through binding T. gondii calcium-dependent protein kinase 1 (TgCDPK1). GRh2 decreased Iba-1 (a specific microglial marker) and NLRP3 inflammasome signaling pathway-related protein expression by binding NLRP3. Co-culture of microglia/primary cortical neurons revealed that T. gondii-induced microglial activation caused neuronal apoptosis, but GRh2 reduced this effect, consistent with the effects of CY-09.

CONCLUSION

Taken together, our results show that GRh2 has a protective effect against T. gondii infection-induced neuronal injury by binding TgCDPK1 and NLRP3 to inhibit NLRP3 inflammasome signaling pathway in microglia.

Ferroptosis, necroptosis, and pyroptosis in the occurrence and development of ovarian cancer

Ovarian cancer (OC) is one of the most common malignancies that causes death in women and is a heterogeneous disease with complex molecular and genetic changes. Because of the relatively high recurrence rate of OC, it is crucial to understand the associated mechanisms of drug resistance and to discover potential target for rational targeted therapy. Cell death is a genetically determined process. Active and orderly cell death is prevalent during the development of living organisms and plays a critical role in regulating life homeostasis. Ferroptosis, a novel type of cell death discovered in recent years, is distinct from apoptosis and necrosis and is mainly caused by the imbalance between the production and degradation of intracellular lipid reactive oxygen species triggered by increased iron content. Necroptosis is a regulated non-cysteine protease–dependent programmed cell necrosis, morphologically exhibiting the same features as necrosis and occurring via a unique mechanism of programmed cell death different from the apoptotic signaling pathway. Pyroptosis is a form of programmed cell death that is characterized by the formation of membrane pores and subsequent cell lysis as well as release of pro-inflammatory cell contents mediated by the abscisin family. Studies have shown that ferroptosis, necroptosis, and pyroptosis are involved in the development and progression of a variety of diseases, including tumors. In this review, we summarized the recent advances in ferroptosis, necroptosis, and pyroptosis in the occurrence, development, and therapeutic potential of OC.

Polysaccharide extract from Isatidis Radix inhibits multiple inflammasomes activation and alleviate gouty arthritis

The polysaccharide extract from Isatidis Radix exhibits potent antiinflammatory and antiviral activities, but the mechanism of Isatidis Radix polysaccharide (IRP) remains obscure. Herein, we reported that IRP blocked the activation of nod-like receptor pyrin domain-containing 3 (NLRP3) inflammasome, leading to the inhibiting of caspase-1 cleavage and IL-1β secretion. Mechanistically, IRP did not inhibit NLRP3 inflammasome through suppressing mitochondrial reactive oxygen species (mtROS) production. However, IRP can significantly suppress the oligomerization of apoptosis-associated speck-like protein (ASC) and subsequently block the formation of inflammasome. Next, we evaluate the role of IRP in monosodium urate (MSU)-induced gout in vivo which is a NLRP3-associated disease. We also observed that oral administration of IRP can reduce the increased ankle thickness and the secretion of IL-1β, IL-18, IL-6, TNF-α and MPO of the mouse ankle joints caused by MSU crystals. Furthermore, flow cytometry analysis highlighted a significant modulation of T helper 17 cells (Th17)/regulatory T cells (Treg) following IRP treatment in MSU induced gout. Overall, our findings suggest that IRP has comprehensive and potent antiinflammatory effects and provide a reasonable therapeutic strategy in preventing inflammasome-associated diseases, such as inflammatory gouty arthritis.

Focus on the Role of the NLRP3 Inflammasome in Multiple Sclerosis: Pathogenesis, Diagnosis, and Therapeutics

Neuroinflammation is initiated with an aberrant innate immune response in the central nervous system (CNS) and is involved in many neurological diseases. Inflammasomes are intracellular multiprotein complexes that can be used as platforms to induce the maturation and secretion of proinflammatory cytokines and pyroptosis, thus playing a pivotal role in neuroinflammation. Among the inflammasomes, the nucleotide-binding oligomerization domain-, leucine-rich repeat- and pyrin domain-containing 3 (NLRP3) inflammasome is well-characterized and contributes to many neurological diseases, such as multiple sclerosis (MS), Alzheimer's disease (AD), and ischemic stroke. MS is a chronic autoimmune disease of the CNS, and its hallmarks include chronic inflammation, demyelination, and neurodegeneration. Studies have demonstrated a relationship between MS and the NLRP3 inflammasome. To date, the pathogenesis of MS is not fully understood, and clinical studies on novel therapies are still underway. Here, we review the activation mechanism of the NLRP3 inflammasome, its role in MS, and therapies targeting related molecules, which may be beneficial in MS.

Tectoridin alleviates lipopolysaccharide -induced inflammaion via inhibiting TLR4-NF-κB/NLRP3 signaling in vivo and in vitro

BACKGROUD

Tectoridin, widely extracted and separated from the rhizome of Iris tectorum Maxium, is extensively reported to have affluent bioactivity, but rarely reported to have anti-inflammatory effects. In this study, we aim to investigate the anti-inflammatory effects and the underlying mechanisms of tectoridin.

METHODS

Here, RAW264.7 macrophages were stimulated with Lipopolysaccharide (LPS) for the inflammation model in vitro. Experimental animals received tectoridin and Dexamethasone (DEX) before LPS injection for endotoxic shock mouse model in vivo. The pro-inflammatory mediators and cytokines in the cell supernatant and serum were detected by ELISA kits. The tissue damages were assessed by biochemical indexes and H&E staining. Immunohistochemistry and Western blot were performed for the detection of proteins.

RESULTS

Our data showed that tectoridin attenuated the LPS-up-regulated nitric oxide (NO), interleukin-6, (IL-6) and interleukin-18, (IL-18) from macrophages and tumor necrosis factor-α, (TNF-α); (IL-6) and (IL-1β) in the serum levels. Besides, our histopathological study showed that the damages caused by LPS in the lung, liver and kidney tissues were decreased. Furthermore, our results demonstrated that tectoridin inhibited the activation of TLR4-NF-κB/NLRP3 signaling proved by immunohistochemistry assay and Western blot.

CONCLUSION

Taken all together, tectoridin might have the potential ability of anti-inflammatory effects and the possible mechanism may be relevant to its inhibition of TLR4-NF-κB/NLRP3 signaling.

Liraglutide attenuate central nervous inflammation and demyelination through AMPK and pyroptosis-related NLRP3 pathway

Aims

Multiple sclerosis (MS) still maintains increasing prevalence and poor prognosis, while glucagon‐like peptide‐1 receptor (GLP‐1R) agonists show excellent neuroprotective capacities recently. Thus, we aim to evaluate whether the GLP‐1R agonist liraglutide (Lira) could ameliorate central nervous system demyelination and inflammation.

Methods

The therapeutic effect of Lira was tested on experimental autoimmune encephalitis (EAE) in vivo and a microglia cell line BV2 in vitro.

Results

Lira administration could ameliorate the disease score of EAE mice, delay the disease onset, ameliorate pathological demyelination and inflammation score in lumbar spinal cord, reduce pathogenic T helper cell transcription in spleen, restore phosphorylated adenosine monophosphate‐activated protein kinase (pAMPK) level, autophagy level, and inhibit pyroptosis‐related NLR family, pyrin domain‐containing protein 3 (NLRP3) pathway in lumbar spinal cord. Additionally, cell viability test, lactate dehydrogenase release test, and dead/live cell staining test for BV2 cells showed Lira could not salvage BV2 from nigericin‐induced pyroptosis significantly.

Conclusion

Lira has anti‐inflammation and anti‐demyelination effect on EAE mice, and the protective effect of Lira in the EAE model may be related to regulation of pAMPK pathway, autophagy, and NLRP3 pathway. However, Lira treatment cannot significantly inhibit pyroptosis of BV2 cells in vitro. Our study provides Lira as a potential candidate for Multiple Sclerosis treatment.

Autoinflammatory Diseases and Cytokine Storms-Imbalances of Innate and Adaptative Immunity

Innate and adaptive immune responses have a well-known link and represent the distinctive origins of several diseases, many of which may be the consequence of the loss of balance between these two responses. Indeed, autoinflammation and autoimmunity represent the two extremes of a continuous spectrum of pathologic conditions with numerous overlaps in different pathologies. A common characteristic of these dysregulations is represented by hyperinflammation, which is an exaggerated response of the immune system, especially involving white blood cells, macrophages, and inflammasome activation with the hyperproduction of cytokines in response to various triggering stimuli. Moreover, hyperinflammation is of great interest, as it is one of the main manifestations of COVID-19 infection, and the cytokine storm and its most important components are the targets of the pharmacological treatments used to combat COVID-19 damage. In this context, the purpose of our review is to provide a focus on the pathogenesis of autoinflammation and, in particular, of hyperinflammation in order to generate insights for the identification of new therapeutic targets and strategies.