Cigarette smoke induces the pyroptosis of urothelial cells through ROS/NLRP3/caspase-1 signaling pathway

Exploring the relationship between pyroptosis and inflammatory bone loss: Evidence from a cigarette smoke-induced osteoporosis mouse model

Smoking is by far one of the greatest public health threats and is recognized as an important predisposing factor for osteoporosis. Exposure to cigarette smoke (CS) has been reported to be associated with inflammation-associated diseases through the induction of pyroptosis. Nevertheless, the correlation between pyroptosis and bone loss induced by CS remains uninvestigated. Here, a mouse model of mainstream smoke exposure-induced osteoporosis was established. μCT, biomechanical testing, and immunohistochemical staining of bone tissue were used to assess the deleterious effects of CS on bone metabolism. In vitro, the effects of cigarette smoke extracts (CSE) on mouse primary bone marrow-derived mesenchymal stem cells (BMSCs) were tested by cell viability assays, gene and protein expression assays, and alizarin red staining. The utilization of the pyroptosis inhibitor MCC950 served to confirm the critical role of BMSCs pyroptosis in CS-induced osteoporosis. Our results indicated that exposure to mainstream smoke led to a notable decrease in the quantity of osteoblasts and hindered the process of osteogenic differentiation in mice. Additionally, there was a significant increase in the expression of pyroptosis-related proteins in the bone marrow. The inhibitory effects of CSE on cell viability and osteogenic differentiation of BMSCs were found to be dose-dependent in vitro. However, the presence of the pyroptosis inhibitor MCC950 significantly improved the impaired osteogenic differentiation and bone mineralization caused by CSE. These results highlight the crucial involvement of BMSCs pyroptosis in the development of bone loss induced by CS. In summary, the findings of this study provide novel evidence that CS exerts a detrimental effect on the process of osteogenesis in BMSCs through the induction of pyroptosis, ultimately leading to bone loss. Inhibition of pyroptosis effectively attenuated the toxicological effects of CS on BMSCs, providing a new target for preventing inflammatory osteoporosis.

Exploring the Cellular Impact of Size-Segregated Cigarette Aerosols: Insights into Indoor Particulate Matter Toxicity and Potential Therapeutic Interventions

Exposure to anthropogenic aerosols has been associated with a variety of adverse health effects, increased morbidity, and premature death. Although cigarette smoke poses one of the most significant public health threats, the cellular toxicity of particulate matter contained in cigarette smoke has not been systematically interrogated in a size-segregated manner. In this study, we employed a refined particle size classification to collect cigarette aerosols, enabling a comprehensive assessment and comparison of the impacts exerted by cigarette aerosol extract (CAE) on SH-SY5Y, HEK293T, and A549 cells. Exposure to CAE reduced cell viability in a dose-dependent manner, with organic components having a greater impact and SH-SY5Y cells displaying lower tolerance compared to HEK293T and A549 cells. Moreover, CAE was found to cause increased oxidative stress, mitochondrial dysfunction, and increased levels of apoptosis, pyroptosis, and autophagy, leading to increased cell death. Furthermore, we found that rutin, a phytocompound with antioxidant potential, could reduce intracellular reactive oxygen species and protect against CAE-triggered cell death. These findings underscore the therapeutic potential of antioxidant drugs in mitigating the adverse effects of cigarette aerosol exposure for better public health outcomes.

ROS induced pyroptosis in inflammatory disease and cancer

Pyroptosis, a form of caspase-1-dependent cell death, also known as inflammation-dependent death, plays a crucial role in diseases such as stroke, heart disease, or tumors. Since its elucidation, pyroptosis has attracted widespread attention from various sectors. Reactive oxygen species (ROS) can regulate numerous cellular signaling pathways. Through further research on ROS and pyroptosis, the level of ROS has been revealed to be pivotal for the occurrence of pyroptosis, establishing a close relationship between the two. This review primarily focuses on the molecular mechanisms of ROS and pyroptosis in tumors and inflammatory diseases, exploring key proteins that may serve as drug targets linking ROS and pyroptosis and emerging fields targeting pyroptosis. Additionally, the potential future development of compounds and proteins that influence ROS-regulated cell pyroptosis is anticipated, aiming to provide insights for the development of anti-tumor and anti-inflammatory drugs.

Pepsin-mediated inflammation in laryngopharyngeal reflux via the ROS/NLRP3/IL-1β signaling pathway

BACKGROUND

Laryngopharyngeal reflux (LPR) is one of the most common disorders in otorhinolaryngology, affecting up to 10% of outpatients visiting otolaryngology departments. In addition, 50% of hoarseness cases are related to LPR. Pepsin reflux-induced aseptic inflammation is a major trigger of LPR; however, the underlying mechanisms are unclear. The nucleotide-binding domain and leucine-rich repeat protein 3 (NLRP3) inflammasome has become an important bridge between stimulation and sterile inflammation and is activated by intracellular reactive oxygen species (ROS) in response to danger signals, leading to an inflammatory cascade. In this study, we aimed to determine whether pepsin causes LPR-associated inflammatory injury via mediating inflammasome activation and explore the potential mechanism.

METHODS

We evaluated NLRP3 inflammasome expression and ROS in the laryngeal mucosa using immunofluorescence and immunohistochemistry. Laryngeal epithelial cells were exposed to pepsin and analyzed using flow cytometry, western blotting, and real-time quantitative PCR to determine ROS, NLRP3, and pro-inflammatorycytokine levels.

RESULTS

Pepsin expression was positively correlated with ROS as well as caspase-1 and IL-1β levels in laryngeal tissues. Intracellular ROS levels were elevated by increased pepsin concentrations, which were attenuated by apocynin (APO)-a ROS inhibitor-in vitro. Furthermore, pepsin significantly induced the mRNA and protein expression of thioredoxin-interacting protein, NLRP3, caspase-1, and IL-1β in a dose-dependent manner. APO and the NLRP3 inhibitor, MCC950, inhibited NLRP3 inflammasome formation and suppressed laryngeal epithelial cell damage.

CONCLUSION

Our findings verified that pepsin could regulate the NLRP3/IL-1β signaling pathway through ROS activation and further induce inflammatory injury in LPR. Targeting the ROS/NLRP3 inflammasome signaling pathway may help treat patients with LPR disease.

Influence of Cigarette Aerosol in Alpha-Synuclein Oligomerization and Cell Viability in SH-SY5Y: Implications for Parkinson's Disease

Although cigarette aerosol exposure is associated with various adverse health issues, its impact on Parkinson's disease (PD) remains elusive. Here, we investigated the effect of cigarette aerosol extract (CAE) on SH-SY5Y cells for the first time, both with and without α-synuclein (α-Syn) overexpression. We found that α-Syn aggravates CAE-induced cell death, oxidative stress, and mitochondrial dysfunction. Fluorescence cross-correlation spectroscopy (FCCS) revealed a dual distribution of α-Syn within the cells, with homogeneous regions indicative of monomeric α-Syn and punctated regions, suggesting the formation of oligomers. Moreover, we observed colocalization of α-Syn oligomers with lysosomes along with a reduction in autophagy activity. These findings suggest that α-Syn overexpression exacerbates CAE-induced intracellular cytotoxicity, mitochondrial dysfunction, and autophagy dysregulation, leading to elevated cell mortality. Our findings provide new insights into the pathogenic mechanisms linking exposure to cigarette aerosols with neurodegenerative diseases.

Therapeutic targets and potential delivery systems of melatonin in osteoarthritis

Osteoarthritis (OA) is a highly prevalent age-related musculoskeletal disorder that typically results in chronic pain and disability. OA is a multifactorial disease, with increased oxidative stress, dysregulated inflammatory response, and impaired matrix metabolism contributing to its onset and progression. The neurohormone melatonin, primarily synthesized by the pineal gland, has emerged as a promising therapeutic agent for OA due to its potential to alleviate inflammation, oxidative stress, and chondrocyte death with minimal adverse effects. The present review provides a comprehensive summary of the current understanding regarding melatonin as a promising pharmaceutical agent for the treatment of OA, along with an exploration of various delivery systems that can be utilized for melatonin administration. These findings may provide novel therapeutic strategies and targets for inhibiting the advancement of OA.

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.

Testicular tissue response following a 90-day subchronic exposure to HTP aerosols and cigarette smoke in rats

Background

Researches have shown that chronic inhalation of cigarette smoke (CS) disrupts male reproductive system, but it is unclear about the mechanisms behind reproductive damages by tobacco toxicants in male rats. This study was designed to explore the effects of heated tobacco products (HTP) aerosols and CS exposure on the testicular health of rats.

Materials and Methods

Experiments were performed on male SD rats exposed to filtered air, HTP aerosols at 10 μg/L, 23 μg/L, and 50 μg/L nicotine-equivalent contents, and also CS at 23 μg/L nicotine-equivalent content for 90 days in five exposure groups (coded as sham, HTP_10, HTP_23, HTP_50 and Cig_23). The expression of serum testosterone, testicular tissue inflammatory cytokines (IL-1β, IL-6, IL-10, TNF-α), reactive oxygen species (ROS), superoxide dismutase (SOD) and malondialdehyde (MDA), NLRP3 inflammasome-related mRNAs and proteins (NLRP3, ASC, and Caspase-1), the degree of pyroptosis and histopathology were investigated.

Results

The results demonstrated that HTP_50 and Cig_23 caused varying degrees of oxidative damage to rat testis, resulting in a decrease of sperm quantity and serum testosterone contents, an increase in the deformity rate, expression levels of proinflammatory cytokines, and NLRP3 inflammasome-related mRNA, and an increase in the NLRP3, ASC, and Caspase-1-immunopositive cells, pyroptosis cell indices, and histopathological damage in the testes of rats. Responses from the HTP_10 and HTP_23 groups were less than those found in the above two exposure groups.

Conclusion

These findings indicate that HTP_50 and Cig_23 induced oxidative stress in rat testes, induced inflammation and pyroptosis through the ROS/NLRP3/Caspase-1 pathway, and destroyed the integrity of thetesticular tissue structure.

Patterns of mutations in nine cancer-related genes and PAF development among smoking male patients diagnosed with bladder cancer

BACKGROUND

Smoking is one of the most popular risk factors provoking bladder cancer (BC). This research intended to estimate cigarette smoking effect involving PAF signs between smoking patients with BC and non-smoking patients with same diagnosis to define relations with pathological characteristics and their prognosis on zero-relapse and disease-associated recovery.

METHODS

Two groups of smokers (n = 54) and non-smokers (n = 62) were selected. Both cohorts of patients had BC. They were evaluated utilizing NGS on 9 cancer-related genes and confirmed through the Sanger DNA sequencing and histopathological tests based on H&E staining. The factor of smoking and impact of PAF development by ELISA assay and PAF-R manifestation in terms of immunochemical evaluation on BC areas comparing to a control group (n = 30) was examined involving healthy contributors, including the use of well-designed statistical trials.

RESULTS

The multivariate evaluation showed considerable rise in mutation patterns related to smoking among BC patients (group 3), increase in PAF development (***P<0.001) and vivid signs of PAF-R contrasted to non-smokers with BC (group 2) and control group (group 1). All the identified biological changes (gains/losses) were recorded at the same locations in both groups. Patients from group 3 held 3-4 various mutations, while patients from group 2 held 1-3 various mutations. Mutations were not identified in 30 respondents from control group. The most repeated mutations were identified in 3 of 9 examined genes, namely TP53, PIK3CA and PTEN, with highest rates of increase in Group 3. Moreover, histopathological tests revealed barely identifiable and abnormal traits in BC tissues, i.e. were without essential histopathological changes between groups 2 and 3.

CONCLUSION

Smoking of cigarettes provokes PAF development due to urothelial inflammation and rise of mutations in 9 cancer-related genes. These are indicative factors of inducing BC.

Hypoxia activates GPR146 which participates in pulmonary vascular remodeling by promoting pyroptosis of pulmonary artery endothelial cells

BACKGROUND

Hypoxia is a risk factor of pulmonary hypertension (PH) and may induce pulmonary artery endothelial cells (PAECs) injury and inflammation. Pyroptosis is a form of cell death through maturation and secretion of inflammatory mediators. However, the mechanistic association of pyroptosis, PAECs injury, and inflammation remain unknown. Here, we explored in detail the effects of hypoxia on pyroptosis of PAECs.

EXPERIMENTAL APPROACH

Using RNA sequencing, we screened differentially expressed genes in pulmonary artery tissue of a Sugen5416/hypoxia-induced (SuHx) rat PH model. We examined the role of the differentially expressed gene G-protein coupled receptor 146 (GPR146) in PAECs through immunohistochemistry, immunofluorescence, CCK-8 assays, western blotings, real-time PCR, detection of reactive oxygen species, and lactate dehydrogenase release experiments.

KEY RESULTS

According to RNA sequencing, GPR146 was 11.64-fold increased in the SuHx-induced PH model, compared to the controls. Further, GPR146 was highly expressed in pulmonary arterial hypertension human lung tissue and SuHx-induced rat PH lung tissues. Our results suggested that the expression of pyroptosis-related proteins was markedly increased under hypoxia, both in vivo and in vitro, which was inhibited by silencing GPR146. Moreover, inhibiting NLRP3 or caspase-1 effectively suppressed cleavage of caspase-1, production of interleukin (IL)-1β, IL-6, and IL-18 in PAECs by hypoxia and overexpression of GPR146.

CONCLUSION

Our results indicated that GPR146 induced pyroptosis and inflammatory responses through the NLRP3/caspase-1 signaling axis, thus triggering endothelial injury and vascular remodeling. Hypoxia may promote PAECs pyroptosis through upregulation of GPR146 and thereby facilitate the progression of PH. Taken together, these insights may help identify a novel target for the treatment of PH.

Pyroptosis and degenerative diseases of the elderly

Pyroptosis is a recently described mechanism of programmed cell death mediated by proteins of the gasdermin family. Widely recognized signaling cascades include the classical, non-classical, caspase-3-dependent gasdermin E and caspase-8-dependent gasdermin D pathways. Additional pyroptotic pathways have been subsequently reported. With the rising prevalence of advanced age, the role of pyroptosis in the degenerative diseases of the elderly has attracted increased research attention. This article reviews the primary mechanisms of pyroptosis and summarizes progress in the research of degenerative diseases of the elderly such as presbycusis, age-related macular degeneration, Alzheimer's disease, intervertebral disc degeneration, and osteoarthritis.

Inflammation triggered by the NLRP3 inflammasome is a critical driver of diabetic bladder dysfunction

Diabetes is a rapidly expanding epidemic projected to affect as many as 1 in 3 Americans by 2050. This disease is characterized by devastating complications brought about high glucose and metabolic derangement. The most common of these complications is diabetic bladder dysfunction (DBD) and estimates suggest that 50-80% of patients experience this disorder. Unfortunately, the Epidemiology of Diabetes Interventions and Complications Study suggests that strict glucose control does not decrease ones risk for incontinence, although it does decrease the risk of other complications such as retinopathy, nephropathy and neuropathy. Thus, there is a significant unmet need to better understand DBD in order to develop targeted therapies to alleviate patient suffering. Recently, the research community has come to understand that diabetes produces a systemic state of low-level inflammation known as meta-inflammation and attention has focused on a role for the sterile inflammation-inducing structure known as the NLRP3 inflammasome. In this review, we will examine the evidence that NLRP3 plays a central role in inducing DBD and driving its progression towards an underactive phenotype.

DNA Damage and Oxidative Stress of Tobacco Smoke Condensate in Human Bladder Epithelial Cells

Smoking is a major risk factor for bladder cancer (BC), with up to 50% of BC cases being attributed to smoking. There are 70 known carcinogens in tobacco smoke; however, the principal chemicals responsible for BC remain uncertain. The aromatic amines 4-aminobiphenyl (4-ABP) and 2-naphthylamine (2-NA) are implicated in BC pathogenesis of smokers on the basis of the elevated BC risk in factory workers exposed to these chemicals. However, 4-ABP and 2-NA only occur at several nanograms per cigarette and may be insufficient to induce BC. In contrast, other genotoxicants, including acrolein, occur at 1000-fold or higher levels in tobacco smoke. There is limited data on the toxicological effects of tobacco smoke in human bladder cells. We have assessed the cytotoxicity, oxidative stress, and DNA damage of tobacco smoke condensate (TSC) in human RT4 bladder cells. TSC was fractionated by liquid-liquid extraction into an acid-neutral fraction (NF), containing polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs, phenols, and aldehydes, and a basic fraction (BF) containing aromatic amines, heterocyclic aromatic amines, and N-nitroso compounds. The TSC and NF induced a time- and concentration-dependent cytotoxicity associated with oxidative stress, lipid peroxide formation, glutathione (GSH) depletion, and apurinic/apyrimidinic (AP) site formation, while the BF showed weak effects. LC/MS-based metabolomic approaches showed that TSC and NF altered GSH biosynthesis pathways and induced more than 40 GSH conjugates. GSH conjugates of several hydroquinones were among the most abundant conjugates. RT4 cell treatment with synthetic hydroquinones and cresol mixtures at levels present in tobacco smoke accounted for most of the TSC-induced cytotoxicity and the AP sites formed. GSH conjugates of acrolein, methyl vinyl ketone, and crotonaldehyde levels also increased owing to TSC-induced oxidative stress. Thus, TSC is a potent toxicant and DNA-damaging agent, inducing deleterious effects in human bladder cells at concentrations of <1% of a cigarette in cell culture media.

The role of inflammation in cadmium nephrotoxicity: NF-κB comes into view

Kidney diseases are major health problem and understanding the underlined mechanisms that lead to kidney diseases are critical research points with a marked potential impact on health. Cadmium (Cd) is a heavy metal that occurs naturally and can be found in contaminated food. Kidneys are the most susceptible organ to heavy metal intoxication as it is the main route of waste excretion. The harmful effects of Cd were previously well proved. Cd induces inflammatory responses, oxidative injury, mitochondrial dysfunction and disturbs Ca²⁺ homeostasis. The nuclear factor-kappa B (NF-κB) is a cellular transcription factor that regulates inflammation and controls the expression of many inflammatory cytokines. Therefore, great therapeutic benefits can be attained from NF-κB inhibition. In this review we focused on certain compounds including cytochalasin D, mangiferin, N-acetylcysteine, pyrrolidine dithiocarbamate, roflumilast, rosmarinic acid, sildenafil, sinapic acid, telmisartan and wogonin and certain plants as Astragalus Polysaccharide, Ginkgo Biloba and Thymus serrulatus that potently inhibit NF-κB and effectively counteracted Cd-associated renal intoxication. In conclusion, the proposed NF-κB involvement in Cd-renal intoxication clarified the underlined inflammation associated with Cd-nephropathy and the beneficial effects of NF-κB inhibitors that make them the potential to substantially optimize treatment protocols for Cd-renal intoxication.

Polyphenols, flavonoids and inflammasomes: the role of cigarette smoke in COPD

COPD is predicted to become the third leading cause of morbidity and mortality worldwide by 2030. Cigarette smoking (active or passive) is one of its chief causes, with about 20% of cigarette smokers developing COPD from cigarette smoke (CS)-induced irreversible damage and sustained inflammation of the airway epithelium. Inflammasome activation leads to the cleavage of pro-interleukin (IL)-1β and pro-IL-18, along with the release of pro-inflammatory cytokines via gasdermin D N-terminal fragment membrane pores, which further triggers acute phase pro-inflammatory responses and concurrent pyroptosis. There is currently intense interest in the role of nucleotide-binding oligomerisation domain-like receptor family, pyrin domain containing protein-3 inflammasomes in chronic inflammatory lung diseases such as COPD and their potential for therapeutic targeting. Phytochemicals including polyphenols and flavonoids have phyto-medicinal benefits in CS-COPD. Here, we review published articles from the last decade regarding the known associations between inflammasome-mediated responses and ameliorations in pre-clinical manifestations of CS-COPD via polyphenol and flavonoid treatment, with a focus on the underlying mechanistic insights. This article will potentially assist the development of drugs for the prevention and therapy of COPD, particularly in cigarette smokers.

This review compiles current investigations into the role of polyphenols/flavonoids in the alleviation of cigarette smoke-induced inflammasome; notably it provides a promising hit for rectifying the treatment of COPD.https://bit.ly/36OcUO9

Electrochemical Mechanical Properties of Beam-Column Joints of Building Steel Structures under Impact Loads

To optimize the seismic performance in high-rise buildings, the performance changes of beam-column joints of high-rise steel structures of buildings when they are impacted are analyzed to obtain the optimal choice of joint combination. The most commonly used steel beam and steel column joints are selected as the research objects. Firstly, the finite element model and the shell element model of the force are established and then the model of the finite element combination of six kinds of steel beam and steel column joints is established. Secondly, the applied data of common impact force in actual buildings are collected, and the simulated impact force in this experiment is established according to the sampled data. Then, the changes in each performance of the joints under the action of the impact external force are deeply explored through simulation. Finally, the accuracy of the model is confirmed by calculation. The experimental results comprehensively show that the transmission mechanisms of the impact force are different for the six joints. Through calculation and comparison, the bending stiffness, strength, deformation, the displacement degree of the joints, and the bearing degree of the impact external force are comprehensively analyzed. It is concluded that the bolt-type and external diaphragm-type steel tube column concrete and steel-beam concrete composite joints have better seismic resistance than the other five joints. The bolt-type does not need to be welded on site, and the on-site construction workers only need to assemble, which can reduce the technical requirements for construction workers, improving the practicability and applicability. Therefore, it shows reliable reference significance for the joint selection of building steel structures.

Inflammasome involvement in CS-induced damage in HaCaT keratinocytes

Cigarette smoke (CS) alters cutaneous biological processes such as redox homeostasis and inflammation response that might be involved in promoting skin inflammatory conditions. Exposure to CS has also been linked to a destabilization of the NLRP3 inflammasome in pollution target tissues such as the lung epithelium, resulting in a more vulnerable immunological response to several exogenous and endogenous stimuli related to oxidative stress. Thus, CS has an adverse effect on host defense, increasing the susceptibility to develop lung infections and pathologies. In the skin, another direct target of pollution, inflammasome disorders have been linked to an increasing number of diseases such as melanoma, psoriasis, vitiligo, atopic dermatitis, and acne, all conditions that have been connected directly or indirectly to pollution exposure. The inflammasome machinery is an important innate immune sensor in human keratinocytes. However, the role of CS in the NLRP1 and NLRP3 inflammasome in the cutaneous barrier has still not been investigated. In the present study, we were able to determine in keratinocytes exposed to CS an increased oxidative damage evaluated by 4-HNE protein adduct and carbonyl formation. Of note is that, while CS inhibited NLRP3 activation, it was able to activate NLRP1, leading to an increased secretion of the proinflammatory cytokines IL-1β and IL-18. This study highlights the importance of the inflammasome machinery in CS that more in general, in pollution, affects cutaneous tissues and the important cross-talk between different members of the NLRP inflammasome family.

The ethanol extract of flower buds of Tussilago farfara L. attenuates cigarette smoke-induced lung inflammation through regulating NLRP3 inflammasome, Nrf2, and NF-κB

ETHNOPHARMACOLOGICAL RELEVANCE

The flower buds of Tussilago farfara L. (Abbreviated as FTF) were widely used in traditional Chinese medicine (TCM) to treat respiratory diseases, including asthma, dry throat, great thirst, turbid saliva, stinky pus, and coughs caused by various causes.

AIM OF STUDY

The aim of study is to explore the efficiency of FTF in vitro and in vivo for the treatment of lung inflammation, and to illustrate the possible mechanisms of FTF in treating inflammation-related respiratory diseases targeting NOD-like receptor 3 (NLRP3) inflammasome, nuclear factor erythroid 2-related factor 2 (Nrf2), and nuclear transcription factor-κB (NF-κB).

METHODS

Lung inflammation model in vivo was induced by exposure of mice to cigarette smoke (CS) for two weeks. The levels of superoxide dismutase (SOD), malondialdehyde (MDA), inflammatory factors, and histology in lung tissues were investigated in presence or absence of ethanol extract of the flower buds of T. farfara L. (FTF-EtOH). In the cell-based models, nitric oxide (NO) assay, flow cytometry assay, enzyme-linked immunosorbent assay (Elisa), and glutathione (GSH) assay were used to explore the anti-inflammatory and anti-oxidant effects of FTF-EtOH. Possible anti-inflammatory mechanisms of FTF targeting NLRP3 inflammasome, Nrf2, and NF-κB have been determined using western blot, quantitative real-time reverse transcriptase-polymerase chain reaction (qRT-PCR), immunofluorescence assay, nuclear and cytoplasmic extraction, and ubiqutination assay.

RESULTS

FTF-EtOH suppressed CS-induced overproduction of inflammatory factors [e.g., tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β)], and upregulation of the content of intracellular MDA in the lung homogenate of mice. In cell-based models, FTF-EtOH reduced the lipopolysaccharide (LPS)-induced overproduction of inflammatory factors, and attenuated the CS extract-induced overgeneration of reactive oxygen species (ROS). Furthermore, FTF-EtOH up-regulated Nrf2 and its downstream genes through enhancing the stability of Nrf2 protein, and inhibited the activation of NF-κB and NLRP3 inflammasome, which have been confirmed by detecting the protein levels in the mouse model.

CONCLUSIONS

FTF-EtOH effectively attenuated lung inflammation in vitro and in vivo. The protection of FTF-EtOH against inflammation was produced by activation of Nrf2 and inhibitions of NF-κB and NLRP3 inflammasome. These datas definitely support the ethnopharmacological use of FTF as an anti-inflammatory drug for treating respiratory diseases in TCM.

Cadmium induces renal inflammation by activating the NLRP3 inflammasome through ROS/MAPK/NF-κB pathway in vitro and in vivo

Cadmium (Cd) has been reported to induce kidney damage by triggering oxidative stress and inflammation. The NLR family Pyrin Domain Containing 3 (NLRP3) inflammasome has been implicated a role in the pathogenesis of inflammation. However, the connection between Cd and NLRP3 inflammasome in the development of renal inflammation remains unknown. In this study, in vitro experiments based on the telomerase-immortalized human renal proximal-tubule epithelial cell line (RPTEC/TERT1) were carried out. Results revealed that CdCl2 (2-8 μM) increased ROS production and activated NLRP3, thereby enhancing secretion of IL-1β and IL-18 (P < 0.05). Knock-down of NLRP3 rescued the RPTEC/TERT1 cells from Cd-induced inflammatory damage. Cd activated the MAPK/NF-κB signaling pathway in RPTEC/TERT1 cells (P < 0.05). In addition, treatment with N-acetylcysteine (NAC) improved inflammation and blocked the upregulation of the MAPK/NF-κB signaling pathway. Pre-treatment with MAPK and NF-κB inhibitors also suppressed NLRP3 inflammasome activation (P < 0.05). Moreover, CdCl2 (25-00 mg/L) stimulated the MAPK/NF-κB signaling pathway, activated the NLRP3 inflammasome, and increased inflammatory response (P < 0.05) leading to renal injury in rats. Exposure to cadmium elevated serum levels of NLRP3 and IL-1β in populations (P < 0.05). Further analysis found that serum NLRP3 and IL-1β levels were positively correlated with urine cadmium (UCd) and urine N-acetyl-β-D-glucosaminidase (UNAG). Overall, Cd induced renal inflammation through the ROS/MAPK/NF-κB signaling pathway by activating the NLRP3 inflammasome. Our research thus provides new insights into the molecular mechanism that NLRP3 contributes to Cd-induced kidney damage.

GLIPR1 Protects Against Cigarette Smoke-Induced Airway Inflammation via PLAU/EGFR Signaling

Background

Chronic obstructive pulmonary disease (COPD) is a major health problem associated with high mortality worldwide. Cigarette smoke (CS) exposure is the main cause of COPD. Glioma pathogenesis-related protein 1 (GLIPR1) plays a key role in cell growth, proliferation, and invasion; however, the role of GLIPR1 in COPD remains unclear.

Methods

To clarify the involvement of GLIPR1 in COPD pathogenesis, Glipr1 knockout (Glipr1-/-) mice were generated. Wild-type (WT) and Glipr1-/- mice were challenged with CS for 3 months. To illustrate how GLIPR1 regulates CS-induced airway damage, knockdown experiments targeting GLIPR1 and PLAU, as well as overexpression experiments of PLAU, were performed with human bronchial epithelial cells.

Results

Compared with WT mice, Glipr1-/- mice showed exacerbated CS-induced airway damage including lung inflammation, airway wall thickening, and alveolar destruction. After CS exposure, total proteins, total white cells, neutrophils, lymphocytes, IL-6, and matrix metalloproteinase-9 increased significantly in lung of Glipr1-/- mice than those in lung of WT mice. Furthermore, in vivo and in vitro experiments demonstrated that silencing of GLIPR1 inactivated PLAU/EGFR signaling and promoted caspase-1-dependent pyroptosis (a mode of inflammatory cell death) induced by CS and CS extract exposure, respectively. In vitro experiments further revealed the interaction between GLIPR1 and PLAU, and silencing of PLAU blocked EGFR signaling and promoted pyroptosis, while overexpression of PLAU activated EGFR signaling and reversed pyroptosis.

Conclusion

To conclude, GLIPR1 played a pivotal role in COPD pathogenesis and protected against CS-induced inflammatory response and airway damage, including cell pyroptosis, through the PLAU/EGFR signaling. Thus, GLIPR1 may play a potential role in COPD treatment.

In vivo assessment of molybdenum and cadmium co-induce nephrotoxicity via NLRP3/Caspase-1-mediated pyroptosis in ducks

Excessive molybdenum (Mo) and cadmium (Cd) cause toxic effects on animals, but their joint effects on pyroptosis in kidney of ducks remain unclear. 160 healthy 7-day-old ducks were randomly divided into four groups which were fed with basal diet containing different dosages of Mo or/and Cd for 16 weeks. On the 4th, 8th, 12th and 16th weeks, kidney tissue and serum were collected. The results showed that Mo or/and Cd could significantly elevate their contents in kidney, disturb the homeostasis of trace elements, cause renal function impairment and histological abnormality, and oxidative stress as accompanied by increasing hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) concentrations and decreasing glutathione peroxidase (GSH-Px), catalase (CAT) and total-superoxide dismutase (T-SOD) activities. Simultaneously, Mo or/and Cd could markedly increase interleukin-1β (IL-1β), interleukin-18 (IL-18) contents and the expression levels of pyroptosis-related genes (NOD-like receptor protein-3 (NLRP3), Caspase-1, apoptosis-associated speck-like protein (ASC), NIMA-related kinase 7 (NEK7), Gasdermin A (GSDMA), Gasdermin E (GSDME), IL-1β and IL-18) and proteins (NLRP3, Caspase-1 p20, ASC and Gasdermin D (GSDMD)). Moreover, the changes of above these indicators were more obvious in combined group. Taken together, the results illustrate that Mo and Cd might synergistically lead to oxidative stress and induce pyroptosis via NLRP3/Caspase-1 pathway, whose mechanism is somehow related to Mo and Cd accumulation in duck kidneys.

Roles of Inflammasome in Cigarette Smoke-Related Diseases and Physiopathological Disorders: Mechanisms and Therapeutic Opportunities

Cigarette smoke damages a wide range of immunological functions, including innate and adaptive immune responses. Emerging literature demonstrates that inflammasome constitutes an essential component in innate immune response. In this review, we focus on the cumulative mechanisms of inflammasome in cigarette smoke-related diseases and physiopathological disorders, and summarize potential therapeutic opportunities targeting inflammasome. This review suggests that inflammasomes (NLRP3, NLRP6, NLRP12 and AIM2) are involved in the pathogenesis of several cigarette smoke-related diseases (including COPD, ALI, atherosclerosis, kidney injury, bladder dysfunction, and oral leukoplakia) and physiopathological disorders (macrophage dysfunction, endothelial barrier dysfunction, podocyte injury, and ubiquitin-mediated proteasomal processing). MyD88/NF-κB, HMGB1, production of ROS, endoplasmic reticulum stress and mitochondrial dysfunction, and Ca²⁺ influx are potentially involved in cigarette smoke induced-inflammasome activation. Strategies targeting ROS/NLRP3 inflammasome axis are most widely investigated and show potential therapeutic effects.

Lipopolysaccharide induces vascular endothelial cell pyroptosis via the SP1/RCN2/ROS signaling pathway

Endothelial cell pyroptosis is a novel cause of endothelial dysfunction in sepsis. Reticulocalbin-2 (RCN2) is involved in regulating vascular inflammation and plays an important role in the cardiovascular system. However, the role of RCN2 in inflammation-induced endothelial cell pyroptosis remains to be explored. Here, we found that RCN2 was upregulated after lipopolysaccharide (LPS) treatment in a concentration- and time-dependent manner. RCN2 knockdown resulted in a significant decrease in pyroptosis, reduced LDH and IL-1β release and ROS production and inhibited the expression of pyroptosis-related proteins (NLRP3, cleaved caspase-1, and cleaved GSDMD) (all p < 0.05). N-acetyl-L-cysteine (NAC) counteracted the effects of RCN2 on pyroptosis (all p < 0.01). The silencing of RCN2 antagonized the inhibitory effect of LPS on the phosphorylation of eNOS (p < 0.05). We predicted and confirmed that specificity protein-1(SP1) could directly bind to the RCN2 promoter and regulate RCN2. RCN2 overexpression rescued the inhibitory effect of SP1 inhibitor on HUVEC pyroptosis induced by LPS (all p < 0.05). These findings suggested that the activation of the SP1/RCN2/ROS signaling pathway could promote LPS-induced endothelial cell pyroptosis.

Cigarette smoke extract induces pyroptosis in human bronchial epithelial cells through the ROS/NLRP3/caspase-1 pathway

AIMS

Pyroptosis and inflammation are involved in the development of chronic obstructive pulmonary disease (COPD). However, the cigarette smoke-mediated mechanism of COPD remains unclear. In this study, we aimed to investigate the role of nucleotide-binding domain-like receptor protein-3 (NLRP3) inflammasome-mediated pyroptosis in the death of human bronchial epithelial (HBE) cells after cigarette smoke extract (CSE) exposure.

MAIN METHODS

The protein level of NLRP3 in lung tissue was measured after cigarette smoke exposure in vivo. In vitro, HBE cells were treated with CSE. Subsequently, the activity of caspase-1, lactate dehydrogenase (LDH) release, release of interleukin (IL)-1β and NLRP3 expression levels were measured. The involvement of reactive oxygen species (ROS) was also explored.

KEY FINDINGS

After exposure to CSE, increased release of LDH, the transcriptional and translational upregulation of NLRP3, the caspase-1 activity levels, and enhanced IL-1β and IL-18 release were observed in 16HBE cells. In addition, NLRP3 was required to activate the caspase-1. Our results suggested that pre-stimulated of 16HBE with a caspase-1 inhibitor, or using NLRP3 siRNA to silence NLRP3 expression, also caused the decrease of IL-1β release and pyroptosis.

SIGNIFICANCES

CSE induced inflammation and contributed to pyroptosis through the ROS/NLRP3/caspase-1 pathway in 16HBE cells. The NLRP3 inflammasome participates in CSE-induced HBE cell damage and pyroptosis, which could provide new insights into COPD.

Inhibition of ROS/NLRP3/Caspase-1 mediated pyroptosis alleviates excess molybdenum-induced apoptosis in duck renal tubular epithelial cells

OBJECTIVE

Excess molybdenum (Mo) is harmful to the body, and the kidney is the vital target organ for Mo exposure. This study focused on the impacts of excess Mo on pyroptosis and the relationship between pyroptosis and apoptosis in kidney.

METHODS

The duck renal tubular epithelial cells were treated with (NH₄)₆Mo₇O₂₄·4H₂O (0, 480, 720 and 960 μM Mo), N-acetyl-L-cysteine (NAC) (100 μM), Z-YVAD-fluoromethylketone (YVAD) (10 μM) and the combination of Mo and NAC or YVAD for 12 h. The LDH release and IL-1β, IL-18 contents of cell supernatant were detected by LDH and ELISA kits. The MMP and ROS level were measured using MMP and ROS kits by flow cytometry. The apoptotic rate of cell was detected by AO/EB counterstaining. Pyroptosis and apoptosis-related factors mRNA and protein levels were assayed by real-time qPCR and western blot, respectively.

RESULTS

Excessive Mo markedly increased LDH, IL-18, IL-1β releases and induced overproduction of ROS, pyroptosis-related factors mRNA and protein levels. NAC and YVAD dramatically decreased pyroptosis induced by Mo. Simultaneously, YVAD significantly changed apoptosis-related factors mRNA and protein levels, and reduced cell apoptotic rate.

CONCLUSION

Excessive Mo exposure can induce pyroptosis by the ROS/NLRP3/Caspase-1 pathway in duck renal tubular epithelial cells, and restraining pyroptosis of Caspase-1 dependence might weaken excess Mo-induced apoptosis. The study provides theoretical basis for excess Mo exposure nephrotoxic researches on waterfowl and the interplay between pyroptosis and apoptosis highlights a new sight into the mechanism of Mo-induced nephrotoxicity.

Inhibition of ROS/NLRP3/Caspase-1 mediated pyroptosis attenuates cadmium-induced apoptosis in duck renal tubular epithelial cells

Cadmium (Cd) is an occupational and environmental pollutant, which mainly causes nephrotoxicity by damaging renal proximal tubular cells. To evaluate the effects of Cd on pyroptosis and the relationship between pyroptosis and apoptosis in duck renal tubular epithelial cells, the cells were cultured with 3CdSO4·8H2O (0, 2.5, 5.0, or 10.0 μM Cd), N-acetyl-L-cysteine (NAC) (100.0 μM), Z-YVAD-FMK (10.0 μM) or the combination of Cd and NAC or Z-YVAD-FMK for 12 h, and then cytotoxicity was assessed. The results evidenced that Cd significantly increased the releases of interleukin-18 (IL-18) and interleukin-1β (IL-1β), lactate dehydrogenase (LDH) and nitric oxide (NO), relative conductivity and cellular reactive oxygen species (ROS) level. Simultaneously, Cd also markedly upregulated NLRP3, Caspase-1, ASC, NEK7, IL-1β and IL-18 mRNA levels and NLRP3, Caspase-1 p20, GSDMD and ASC protein levels. Additionally, NAC notably improved the changes of above indicators induced by Cd. Combined treatment with Cd and Z-YVAD-FMK remarkably elevated Bcl-2 mRNA and protein levels, inhibited p53, Bax, Bak-1, Cyt C, Caspase-9 and Caspase-3 mRNA levels and p53, Bax, Bak-1, Caspase-9/cleaved Caspase-9 and Caspase-3/cleaved Caspase-3 protein levels, increased mitochondrial membrane potential (MMP), decreased apoptosis ratio and cell damage compared to treatment with Cd alone. Taken together, Cd exposure induces duck renal tubular epithelial cell pyroptosis through ROS/NLRP3/Caspase-1 signaling pathway, and inhibiting Caspase-1 dependent pyroptosis attenuates Cd-induced apoptosis.

The roles of endothelin and its receptors in cigarette smoke-associated pulmonary hypertension with chronic lung disease

Chronic exposure to cigarette smoke is the major risk factor for the development of pulmonary hypertension (PH) with chronic lung disease (i.e. PH group III). The pathogenesis of smoke-associated PH group III in chronic obstructive pulmonary disease (COPD) involves cigarette smoke exposure-induced damage to lung tissue and dysfunction of pulmonary system with increased synthesis and release of endothelin-1 (ET-1), hypoxia, inflammation, pulmonary vascular remodeling. Many studies have demonstrated that cigarette smoke exposure induces activation of mitogen-activated protein kinase (MAPK) signal pathway that leads to up-regulation of ET-1 and its receptors with the receptor-mediated enhanced contraction, proliferation of pulmonary vascular smooth muscle cells, pulmonary vascular remodeling, elevated pulmonary arterial pressure and finally PH group III. This mini-review article aims to summarize the current state of understanding on the roles of cigarette smoke-induced up-regulation of ET-1 and its receptors in the development of PH group III. Understanding the underlying molecular mechanisms that cigarette smoke exposure leads to PH group III may provide a novel strategy for the treatment.

LncRNA ADAMTS9-AS2 inhibits gastric cancer (GC) development and sensitizes chemoresistant GC cells to cisplatin by regulating miR-223-3p/NLRP3 axis

The role of LncRNA ADAMTS9-AS2 in the regulation of chemoresistance of gastric cancer (GC) is largely unknown. Here we found that LncRNA ADAMTS9-AS2 was low-expressed in GC tissues and cells compared to their normal counterparts. In addition, LncRNA ADAMTS9-AS2 inhibited miR-223-3p expressions in GC cells by acting as competing endogenous RNA, and the levels of LncRNA ADAMTS9-AS2 and miR-223-3p showed negative correlations in GC tissues. Of note, overexpression of LncRNA ADAMTS9-AS2 inhibited GC cell viability and motility by sponging miR-223-3p. In addition, the levels of LncRNA ADAMTS9-AS2 were lower, and miR-223-3p was higher in cisplatin-resistant GC (CR-GC) cells than their parental cisplatin-sensitive GC (CS-GC) cells. LncRNA ADAMTS9-AS2 overexpression enhanced the cytotoxic effects of cisplatin on CR-GC cells, which were reversed by overexpressing miR-223-3p. Furthermore, LncRNA ADAMTS9-AS2 increased NLRP3 expressions by targeting miR-223-3p, and upregulation of LncRNA ADAMTS9-AS2 triggered pyroptotic cell death in cisplatin treated CR-GC cells by activating NLRP3 inflammasome through downregulating miR-223-3p. Finally, the promoting effects of LncRNA ADAMTS9-AS2 overexpression on CR-GC cell death were abrogated by pyroptosis inhibitor Necrosulfonamide (NSA). Collectively, LncRNA ADAMTS9-AS2 acted as a tumor suppressor and enhanced cisplatin sensitivity in GC cells by activating NLRP3 mediated pyroptotic cell death through sponging miR-223-3p.